Problems after HIFU and Radiofrequency: Burns, Numbness, Nerve Effects, Fat Loss — What Can Be Done?

What is normal after HIFU and radiofrequency?

HIFU (focused ultrasound) and radiofrequency aim to stimulate collagen production by heating the deeper layers of the skin in a controlled way. Because of this heat, redness, a feeling of warmth and mild swelling are common immediately after the procedure. After HIFU, a mild ache when chewing or touching the area can last a few days, sometimes a few weeks; temporary raised lines may also appear on the skin.

After radiofrequency microneedling, redness, swelling, small pinpoint marks and mild crusting usually last a few days. For the general features of these procedures, see our articles “HIFU (High-Intensity Focused Ultrasound)” and “Radiofrequency Skin Tightening and Radiofrequency Microneedling”.

Why do HIFU or radiofrequency burns happen, and how can you recognise them?

A burn occurs when the energy is concentrated too much on the skin surface or in a layer very close to it. Using a transducer set to the wrong depth, delivering repeated pulses to the same spot, the handpiece not being in full contact with the skin, high energy in thin-skinned areas close to bone and a poorly maintained device can all increase this risk. With radiofrequency, keeping the handpiece still in one place can also cause a burn.

HIFU burns often appear as lines or rows of dots along the treatment line, while radiofrequency microneedling burns appear as grid or square patterns matching the shape of the handpiece. In the first hours there may be marked redness and burning, followed by blistering or crusting. Most superficial burns heal with appropriate wound care; with deep burns, however, scarring and discolouration may remain.

Darkening or lightening of the skin can also occur after a burn; this risk is higher in darker skin. For similar problems with laser and light treatments, see our article “Burns and Pigmentation Changes after Laser and IPL”.

How long do numbness and tingling last?

Heat can temporarily affect the fine sensory nerves under the skin. In this case, numbness, tingling or an altered sensation to touch develops in the area. In published reports these symptoms are mostly temporary and subside within weeks or months; however, it is not possible to give a definite duration.

If the numbness is spreading, getting worse together with pain, or not decreasing after several weeks, it should be shown to a physician. The physician will distinguish whether the symptom is due to a sensory nerve or to a motor nerve being affected.

An uneven smile: could a nerve be affected?

Rarely, the nerve branches that move the facial muscles have been reported to be affected by heat. The area most often affected is the lower face and jawline: when you smile, one corner of the mouth may move differently, one side of the lower lip may not move down, or the lips may look asymmetrical. In the brow area, there may be difficulty raising the eyebrow.

In reported cases, most of these effects are temporary and resolve within weeks or months. Even so, any newly appearing loss of movement should be reported to a physician the same day. The physician will assess whether the symptom is related to the procedure, refer you if needed to relevant specialties such as neurology, and follow the recovery.

Can HIFU or radiofrequency cause hollowing and fat loss in the face?

With HIFU and some radiofrequency devices that deliver heat to deep layers, hollowing or loss of volume due to loss of the fat tissue under the skin has rarely been reported. This may be more noticeable especially in people with a slim face, in areas such as the cheeks and around the mouth. The change is often noticed weeks after the procedure.

Information on how often this risk occurs, in whom it is more likely and how far it improves on its own is limited. In some people the appearance may become less noticeable over time; if the loss of volume does not go away, the physician may, where appropriate, consider volume-restoring treatments. Trying to correct it with another energy-based treatment can make the situation worse.

What problems are specific to radiofrequency microneedling?

Because the needles enter the skin in radiofrequency microneedling, some additional problems besides burns and pigmentation can occur: grid- or track-like marks matching the shape of the handpiece, prolonged darkening, infection, an acne-like rash and cold sore flare-ups. A non-sterile needle tip, or applying an unsuitable product to the skin after the procedure, can increase the risk of infection and tissue reaction.

In a safety communication published in 2025, the U.S. Food and Drug Administration (FDA) announced that burns, scarring, fat loss, disfigurement and nerve damage had been reported after some radiofrequency microneedling procedures, with surgical repair needed in some cases. The agency stressed that this is a medical procedure and that these devices should not be used at home.

Are home HIFU and radiofrequency devices safe?

Reliable data on the effectiveness and safety of HIFU and radiofrequency devices sold for home use are limited. The wrong depth, repeated application to the same spot and an inappropriate energy level can lead to burns and nerve effects. It is also unclear who is responsible and how you will be helped if a problem arises.

In some countries, reports of burns and nerve damage after HIFU treatments carried out in beauty salons by people without medical training have been the subject of official warnings. For devices of unknown origin and treatments outside healthcare facilities, see our article “Counterfeit Products and Unlicensed Treatments”.

If there is a problem, what should you do at home, and what should you avoid?

1. Note the symptoms and when they started; take photos at regular intervals in the same lighting.
2. If you have any of the warning signs, call the physician who performed the procedure the same day; find out which device and which handpiece were used.
3. If your physician recommends it, keep the area clean and covered and follow the recommended wound care.
4. Protect the area from the sun; use a broad-spectrum sunscreen during healing and afterwards.
5. If you cannot reach your physician and you have an open wound, fever or loss of facial movement, go to an emergency department and say which procedure you had.

• Do not burst blistered areas or pick off crusts.
• Do not apply heat to an area where a burn is suspected, and avoid saunas and steam baths; if you use ice, wrap it in a cloth rather than putting it directly on the skin, and apply it only briefly.
• Do not apply creams you have at home on your own, especially prescription steroid or antibiotic products.
• Do not use acid-containing, retinoid or irritating skin care products until your physician allows it.
• Do not have another device treatment, a peel or filler in the same area to fix the problem.
• Do not treat the area again with a home HIFU or radiofrequency device.

What are the treatment options? What can the physician do?

The physician will first assess whether the problem is part of the expected healing or a complication such as a burn, infection, nerve effect or fat loss. For burns, wound care is planned and the area is monitored for signs of infection. If an infection is suspected, appropriate medication can be started; for a cold sore flare-up, the physician also plans the necessary treatment.

When a nerve is affected, follow-up and patience are often needed; the physician documents the course of recovery and, if needed, refers you to relevant specialties. For pigmentation and scarring after a burn, suitable treatments can be discussed once healing is complete. With loss of volume, the area is first monitored for a while; then, if appropriate, volume-restoring options can be considered. 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?

• Have the procedure done under the responsibility of a physician who knows facial anatomy, especially the areas where the nerves run, in a licensed healthcare facility.
• Ask which device will be used, whether it is registered as a medical device and whether it is regularly maintained.
• If you have a slim face or loss of volume in your cheeks, discuss this; the areas to receive deep heating can be planned accordingly.
• Mention in advance if you have a pacemaker or another implanted device, metal implants, filler or a thread lift.
• Do not have the procedure on tanned or sunburnt skin.
• If you feel excessive burning or sharp pain during the procedure, say so immediately; the energy can be adjusted or the treatment stopped.
• Stay away from home HIFU and radiofrequency devices and from treatments outside healthcare facilities.

Limits of the evidence: how often complications of HIFU and radiofrequency occur varies greatly depending on the device, the handpiece, the energy level and the practitioner. Most published studies are small with short follow-up; rare problems such as fat loss and nerve effects are mostly known from case reports and voluntary reporting systems. For this reason, you cannot be given a personal risk figure. This page is for general information and does not replace an examination.