What are the side effects of Thermage® FLX?

This is because excessive energy affecting the fat layer beneath the dermis can cause fat atrophy. When the fat supporting facial volume decreases, the cheeks can appear sunken or the contours can become irregular, which is why it is often mentioned under the keyword “Thermage® FLX volume loss.” When performed safely, this is a rare side effect with current protocols.

Another point is that after the temporary swelling from the procedure subsides, pre-existing volume loss (fat loss due to aging) may become relatively more noticeable. For individuals with little facial fat, the energy intensity and treatment area can be adjusted at the diagnostic stage before the procedure, and if needed, combining a procedure that helps build facial volume may be considered.

Yes, mild redness, swelling, and a warm sensation lasting from a few hours to 1–2 days after the procedure are mostly normal reactions. This is a natural process that occurs as heat is delivered to the dermis, and it can be a sign that collagen remodeling has begun. It typically subsides without any special treatment, and as long as you avoid saunas, alcohol, and strong UV rays on the day of the procedure, it usually does not interfere with daily life.

However, if redness persists for more than a few days or is accompanied by blisters or pain, it may fall outside the range of a normal reaction, so it is advisable to contact the clinic where you received the treatment.

Three key factors are: whether a genuine tip is used, the experience of the practitioner, and a treatment plan tailored to your individual skin condition. The Thermage® FLX tip is a single-use consumable, so you can request to see it opened and verified as genuine before the procedure; this is the most basic safety measure to reduce device-related risks such as burns.

The practitioner factor is also important. Experience with adjusting energy and shot distribution according to skin thickness and fat volume for each facial area, and adjusting intensity based on the patient's pain feedback during the procedure, can help prevent side effects. We recommend checking whether a board-certified dermatologist is involved in the diagnosis and treatment design, and whether a sufficient pre-procedure assessment of skin condition (inflammation, previous treatments, metal implants, etc.) is performed.

If you experience abnormal symptoms such as blisters, pigment changes, skin indentation, or prolonged pain, you should contact the clinic where you received the treatment as soon as possible. In particular, if blisters are popped or left untreated, they can lead to hyperpigmentation or scarring, so early management is important. The sooner you respond, the faster the recovery and the lower the chance of lasting marks.

The clinic will provide step-by-step care such as soothing and regenerative treatments or pigment management, depending on the symptoms. Keeping a record of photos taken immediately after the procedure and the timing of symptom onset can be helpful for diagnosis. It is safest to receive care from a clinic that has a system for managing side effects, from pre-procedure consultation through to follow-up care, so we recommend discussing any questions thoroughly with a board-certified dermatologist.