Problems after Fractional Laser: Dark Spots, Cold Sores, Acne, Scars

What is normal after fractional laser?

Fractional laser creates many small, separate treatment zones in the skin; as the skin repairs these zones, redness, swelling, a feeling of warmth, dryness and fine peeling are expected symptoms. With non-ablative treatments, the skin may take on a dark or bronze colour for a few days. With ablative treatments, oozing and crusting in the first days are also part of healing.

The time considered normal depends on the type of laser and the intensity of the treatment: with non-ablative treatments, symptoms usually decrease within a few days; with ablative treatments, the surface takes longer to heal and redness can continue for weeks. For the procedure itself and a day-by-day aftercare timeline, see our article “Fractional Laser”. What really matters is that the symptoms decrease as the days pass; if they are increasing, healing may have departed from the expected course.

Why does redness last longer, and when should you worry?

Redness lasting longer than expected is called prolonged erythema. It is more common after ablative and intensive treatments, in sensitive skin, in people with rosacea or eczema and in those who use irritating products during the healing period. It often decreases over time; however, redness that comes with hardening, raised areas or itching can be an early sign of a developing scar.

So if redness lasts longer than expected, increases again or becomes more pronounced in one area, see a physician. The physician will rule out other causes such as infection or contact allergy and may change your care routine.

Dark spots after fractional laser: darkening and lightening of the skin

Post-inflammatory hyperpigmentation, that is, darkening of the skin that develops as it heals, is one of the known unwanted effects of fractional laser. It is more common in medium and darker skin, in skin that easily develops dark spots and in skin exposed to the sun after the procedure. The intensity of the treatment and heat build-up also affect the risk. It usually fades within weeks to months; the time varies from person to person. For precautions specific to darker skin, see our article “Laser, IPL and Chemical Peels on Olive and Darker Skin”.

Less commonly, the skin may remain lighter than its surroundings (hypopigmentation). This has been reported particularly after ablative and intensive treatments; it can sometimes appear months later and may not reverse. For more information about colour changes and burns, see our article “Burns and Pigmentation Changes after Laser and IPL”.

Acne-like breakouts and milia

During the healing period, small acne-like spots and small white cysts called milia may appear. These are among the most frequently reported problems after fractional laser; heavy moisturisers or occlusive products can contribute. Most are temporary. Spots that are increasing in number, painful or inflamed, however, should be shown to a physician because they can be confused with an infection; do not squeeze spots. For details, see our article “Spots and Milia (White Cysts) after Laser and Peels”.

Can fractional laser trigger cold sores?

Yes. In people who have had cold sores before, laser can reactivate the cold sore virus; it can also occur in people with no known history of cold sores. It usually appears in the first days, around the mouth or anywhere in the treated area, as clusters of small fluid-filled blisters or painful sores. Because it can spread across healing skin and increase the risk of scarring, it is important to have it assessed the same day.

Whether preventive cold sore medication is given is decided by the physician according to the type of laser, the treatment area and your history. So be sure to mention your history of cold sores before the procedure.

How can infection be recognised?

Skin left exposed, especially after ablative treatments, can be an entry point for bacteria and fungi. Increasing pain, warmth, swelling, yellow crusting, yellow-green discharge, a bad smell and fever suggest a bacterial infection. A fungal infection, on the other hand, may appear as an itchy rash with small blisters.

Infection delays healing and increases the risk of scarring. With these symptoms, the area needs to be seen by a physician; if necessary, a sample is taken and appropriate treatment is started. For general information, see our article “Infection after Aesthetic Treatments”.

Itching and rash: could it be a contact allergy?

Contact dermatitis (skin irritation or an allergic reaction) can develop to the creams, ointments or skincare products used during the healing period. Intense itching and raised redness that spreads beyond the treated area suggest this. In that case, stop trying new products and see your physician. For allergic symptoms, see our article “Allergic Reactions in Aesthetic Treatments”.

Can fractional laser leave a scar?

Scarring is an uncommon but important problem. It is seen mainly after ablative and intensive treatments, infection, cold sore flare-ups and picking off crusts. Areas where the skin is thin or heals slowly, such as the neck, chest and eyelids, are at higher risk; more cautious settings are usually preferred in these areas. After intensive ablative treatments around the eyes, the lower eyelid pulling outwards and downwards (ectropion) has rarely been reported.

Prolonged and thickening redness, hardening lines or raised areas can be the first sign of a developing scar. When a tendency to scarring is noticed early, the physician can often intervene; so show these signs without waiting. For more information about scars, see our article “Scars and Keloids”.

Eye safety

In laser treatments on the face, the eye is an organ that can easily be harmed; the risk increases when the eyelids and the area around the eyes are treated. In most reported eye injuries, protection was not used or was removed during the procedure. For this reason, you should wear suitable eye protection throughout the procedure, and if the area around the eyes is being treated, any additional protection the physician considers necessary should be used. Eye pain or a change in vision after the procedure is a situation that needs to be assessed without waiting.

If you have taken isotretinoin

If you are taking an oral vitamin A-derived acne medicine (isotretinoin) or have recently stopped it, be sure to say so before the procedure. Whether a waiting period is needed is assessed by your physician according to the type and extent of the laser treatment. For the current approach, see our article “Medical Aesthetics for People on Medication or with Chronic Conditions”.

What should you do if there is a problem?

1. If you have eye pain or a change in vision, or if shortness of breath or swelling of the lips or tongue develops, call 112 without waiting.
2. If you have any of the warning signs, call the physician who performed the procedure the same day; take a photo of the area and say which type of laser was done, when, and which products you use.
3. Follow the cleaning and care instructions your physician gave you; do not try any new product your physician has not recommended.
4. Protect yourself strictly from the sun: with shade, a hat and clothing; once the skin has closed, with the sunscreen your physician recommends.
5. If you cannot reach your physician and you have a fever, rapidly spreading redness or severe pain, go to an emergency department.

What should you not do?

• Do not pick off crusts or peeling skin, squeeze spots or scratch.
• Do not apply steroid, antibiotic, cold sore or skin-lightening creams unless a physician recommends them; do not treat yourself with prescription medicines.
• Do not use home remedies such as toothpaste, lemon, vinegar, cologne or plant oils.
• Until the skin has healed, do not use make-up, retinoids or acid products, do not scrub with an exfoliating mitt, use a sauna, steam room or swimming pool, or have a new procedure.
• Do not sunbathe or use a sunbed; remember that even brief sun exposure can make dark spots worse.

What can a physician do?

The physician first determines whether the problem is expected healing, an infection, a cold sore, a contact allergy or a developing scar. For infections and cold sores, appropriate medication can be started; if necessary, a sample is taken. For an allergy, the triggering product is stopped and treatments to soothe the skin can be planned. With prolonged redness and a tendency to scarring, early treatments aimed at reducing scar formation can be considered; eyelid problems may need follow-up together with an eye specialist.

If a dark spot develops, the basic approach is sun protection and time; if necessary, the physician may recommend skin-lightening treatments. A new laser session on the same area is usually planned after the skin has healed and colour problems have receded. For the general process, see our article “What Should You Do If a Complication Occurs after an Aesthetic Treatment”.

What can be done to reduce the risk?

• Decide on the type and intensity of the laser together with a physician who assesses your skin type and the treatment area.
• Before the procedure, mention your history of cold sores, the medicines you take (especially isotretinoin), retinoid and acid products, and any previous problems with dark spots or scarring.
• Do not sunbathe or tan before the procedure; choose a period when you can protect yourself strictly from the sun afterwards.
• If you have darker skin or a tendency to dark spots, follow the pigmentation prevention plan your physician recommends.
• Ask whether a more cautious plan will be made for sensitive areas such as the neck, chest and around the eyes.
• Do not remove your eye protection during the procedure.
• During the healing period, follow your physician’s care instructions and do not miss follow-up appointments.

Limits of the evidence: how often fractional laser complications occur varies greatly depending on the type of laser, its settings, the treatment area and the skin type. Much of the available information is based on single-centre retrospective studies, case reports and reviews; because devices and settings differ between studies, the results cannot be directly applied to one another. For this reason, you cannot be given a personal risk figure. This page is for general information and does not replace an examination.