Ultherapy and Thermage share the same common reactions, redness and mild swelling, and part ways on the rare ones. Ultherapy focuses ultrasound at points deep under the skin, so bruising, numbness and, rarely, temporary weakness of a facial nerve have been reported. Thermage heats a broad area closer to the surface with radiofrequency, so its rare risk is a blistering second-degree burn.

That difference changes what you should watch for in the days afterward. In this article, we'll cover how each device delivers heat, the rare side effects reported for each, which reactions can wait and which can't, how they combine with injectables and how to plan either one around a trip.

Quick summary

• Redness and swelling are common to both; the rare risks lean toward nerves with Ultherapy and toward surface burns with Thermage.

• Normal range: in 20 Korean patients after one Ultherapy session, 6 had redness or swelling and 2 had bruising, and all of it cleared within 2 weeks.

• With an older Thermage model, second-degree burns showed up in 21 of 5,858 pulses (0.36%).

• Blisters, oozing or one corner of your mouth moving oddly are reasons to contact the clinic right away.

Do Ultherapy and Thermage Cause the Same Side Effects at First?

Yes, the reactions you'll most likely notice on the day are the same for both: a flushed face and slight puffiness where the device passed. Both treatments use heat to prompt new collagen, so the heated tissue swells a little for a short while. Once the redness fades, most people can wear makeup again right away.

The difference starts with the shape of the heat. Ultherapy places tiny points of heat at set depths, from the deep dermis down to the SMAS* layer. In the 20-person study above, the probes were set to 3.0 mm and 4.5 mm. Thermage warms a broad, even area of dermis under the tip that touches your skin, so the heat sits closer to the surface.

*SMAS: the thin sheet of tissue that wraps the facial muscles and holds the skin up from below. Surgical facelifts tighten this same layer.

In that Ultherapy study, every reaction was mild and passed without a mark. Over 6 months of follow-up, nobody had nerve pain, nerve weakness, severe swelling, blisters or fat loss. It was a small group and a single session, so how your skin responds may differ.

What Rare Side Effects Are Reported After Ultherapy?

Ultherapy's rare reactions trace back to that deep, focused heat. Bruising, raised lines along the treatment rows (welting) and patches of numbness or tingling have been reported. Brief weakness of a nerve that moves the mouth or forehead has also been seen. In reports where the device was used as intended, these tended to fade without lasting effects.

Rarer still is heat that reaches the surface. A case series of 5 patients described blistering, open sores, swelling followed by a dip in the skin (atrophy) and, in some, dead skin after a single Ultherapy session. The authors noted these events are rare but may be underreported, and that early wound care matters for healing.

Keep in mind that 5 cases can't tell you how often this happens. What it does tell you is the kind of change to report quickly: anything that looks like a blister or a raw patch, rather than simple redness.

What Rare Side Effects Are Reported After Thermage?

Because Thermage heats a wide area near the surface, a burn is its signature rare risk. In a study of 86 people who had one session with an older Thermage model, second-degree burns with blistering occurred in 21 of 5,858 pulses (0.36%). Six months later, 3 people had small scars.

A Spanish clinic reviewing 757 sessions in 290 patients found second-degree burns in 2.7% of sessions. Persistent redness came up in 1.22%. Fat loss that leaves a dent, scarring and nerve pain were rarer still. Both sets of numbers come from older tips and settings, so they don't describe current devices directly.

The review's authors linked overheating to high energy and to passing over the same spot back to back. Moderate energy without immediate overlap was their advice. That's also why it matters to speak up during treatment: if the heat feels like too much, say so rather than pushing through.

Which Reactions Can Wait, and Which Need a Call Right Away?

Redness, mild swelling, small bruises and tenderness when you press the area are passing reactions with either device. In the Ultherapy study above, they had cleared within 2 weeks. Contact the clinic right away, without waiting it out, if you notice any of these:

• A blister, or skin that starts to ooze

• Skin that breaks down, crusts or turns dark

• One corner of your mouth moving oddly when you smile or talk

• Numbness that spreads to a wider area

• One spot that looks sunken once the swelling has gone down

If the skin looks infected, with spreading redness, fever or worsening pain, seek medical care right away. Keep blisters intact and don't pick at crusts.

It's also better to put off either treatment in these cases*:

• You're pregnant

• There's a skin infection in the area to be treated

• You take certain medications (bring a list of what you take to your visit)

*Based on American Academy of Dermatology guidance for patients.

Is It Safe to Get Botox or Filler Around the Same Time?

Combining these devices with injectables on a planned schedule has a reassuring track record. A chart review from two Korean clinics covered 1,040 people treated between 2005 and 2023 who had Ultherapy-type ultrasound or Thermage-type radiofrequency along with Botox or filler. No burns, infections, dead skin or filler migration were recorded.

What did show up was tied to the injectable. Three people who also had Botox developed a drooping eyelid (0.4%), and 2 who had hyaluronic acid filler had uneven surface texture. The study looked back at records from two clinics only, so it can't prove the combination is risk-free for everyone.

Order and spacing depend on where the injection went and when. Before booking, tell the clinic the date and area of any Botox or filler you've had in the past few months.

Fitting Ultherapy or Thermage Into a Trip to Seoul

Unless you've had sedation that day, there's no need to postpone your flight because of Ultherapy or Thermage. For Ultherapy at up to around 300 shots, swelling usually barely shows, which makes photos and sightseeing easier to plan.

One visit is a starting point rather than a finished result. These treatments don't change your face dramatically overnight. Over the following months, your skin tends to move closer to how it looked a little earlier. Results differ from person to person, and how much you see depends on your skin.

Once you're home, you can send photos to the clinic through the consultation button on this page if you're unsure whether a reaction is normal. If you have a blister that's spreading, signs of infection or facial weakness that's getting worse, see a local doctor first rather than waiting for a reply.

The Bottom Line: Ask About Depth and Heat Before You Choose

With both devices, the depth and strength of the heat are set to your face shape and the layer that's sagging. I start by looking at the balance of your whole face and the difference between your left and right sides, then decide where the heat should go. Before you decide, ask: "For Ultherapy, which depths would you use for me, and for Thermage, what level of heat?" That one answer lets you compare the two on the same terms.

If side effects are your main concern, talk to your provider before deciding. Beautystone is a clinic in Seoul's Hapjeong area. When you reach out, include any blistering or numbness you've had after past lifting treatments and when it happened, the dates of recent Botox or filler and the dates you'd like to come in.

Sources

• Reactions and results after one Ultherapy session in 20 Korean patients (Ann Dermatol, 2015)

• Five cases of blistering, sores and skin loss after Ultherapy (Lasers Surg Med, 2018)

• Burn rate in 86 people after one Thermage session around the eyes (Lasers Surg Med, 2003)

• Side effects across 757 radiofrequency sessions in 290 patients (J Cosmet Dermatol, 2007)

• Safety of ultrasound or radiofrequency lifting with injectables in 1,040 patients (Arch Dermatol Res, 2025)

• Common reactions to nonsurgical skin tightening and who should wait (American Academy of Dermatology)