In short. The transducer, the depth lines, the heat of each pass, and the point at which the operator decides to stop. What an hour in the treatment room is actually like.

Key points

  • The session ends at a boundary decided in advance rather than at a number reached.
  • The layer being treated sits close to a small sensory nerve in some places and close to a compartment of fat in others, and continuing past the planned boundary there trades a small gain for a real risk.
  • Ask afterwards which areas were treated, which were left, and why.

A session of this treatment is not a procedure in the way an operation is. There is no theatre, no anaesthetic, no wound and no recovery room. It is an hour of a clinician passing a handpiece over your face and neck, deciding depth and deciding where to stop.

Before the handpiece

The face is cleaned, and the plan made at the assessment is translated into areas to treat and areas to leave. Photographs are taken in standardised light before treatment, because the review at two to three months is judged against them. The depth for each area is decided now rather than adjusted mid-session.

What you feel

Each pass delivers energy at a chosen depth, and what most people report is heat and a deep ache at the moment of delivery rather than pain at the surface. The sensation is brief and it moves with the handpiece. Where it is sharper than expected the operator adjusts rather than continues, and that adjustment is a normal part of the session rather than a sign that something has gone wrong. The jawline and the temple are commonly reported as the sharpest areas and the neck as the least.

Where the operator decides to stop

The session ends at a boundary decided in advance rather than at a number reached. The layer being treated sits close to a small sensory nerve in some places and close to a compartment of fat in others, and continuing past the planned boundary there trades a small gain for a real risk. Ask afterwards which areas were treated, which were left, and why.

How long it takes

A single session covering the face and neck takes about an hour, and some plans use one longer session while others spread the same work over a series of shorter ones. The choice is a judgement about the area to cover, how much discomfort is reasonable to accept in one sitting, and how the skin responded last time. Spreading the work over a series does not make the total effect larger.

Afterwards, in the room

There is no dressing and no wound care instruction, because there is no wound. You leave with the treated area tender and possibly slightly swollen, and with washing, skincare and exercise unrestricted. Any numbness or tingling is written down before you leave, so that the review compares against a record rather than a memory.

Stop the session and say so if

  • The sensation in one spot is sharp and unlike the rest of the pass, or it is not settling between passes.
  • You feel anything spreading, or any numbness developing during the session rather than after it.
  • You are being asked to accept more discomfort than you agreed to, or the plan has changed without being explained.

What decides the depth in the first place is set out in The Depth Setting Decides the Result. What usually follows a session is described in Numbness, Nerve Weakness and the Rare Ultrasound Risks.

Related reading

Frequently asked questions

Is a session painful?

Most people describe heat and a deep ache at the moment each pass delivers energy, rather than surface pain, and the sensation moves with the handpiece. Some areas are more sensitive than others. Where it is sharper than expected the operator adjusts, and adjusting is a normal part of a session rather than a complication.

Do I need someone to come with me, or time off afterwards?

Neither is usually necessary. There is no anaesthetic and no wound, so most people return to work the same day or the next and drive themselves home. Tenderness over the treated area for a few days is usual, and it does not prevent ordinary activity, skincare or exercise.

Why are photographs taken before treatment rather than at the end?

Because the review is judged against them. A change of this size is not detectable from memory or from a mirror, and a photograph taken afterwards is not comparable with one taken before. Standardised light, distance and time of day are what make the comparison meaningful at two to three months.

Risks & Limitations

  • The result builds slowly and modestly, over roughly two to six months, and no outcome can be guaranteed. At the review point, more sessions of the same treatment are unlikely to be the answer if a standardised photograph shows nothing measurable.
  • Patches of numbness and tingling over the treated area are common after a session. They usually settle over days to weeks, and a patch that spreads rather than shrinks, or that is unchanged after several weeks, requires assessment.
  • Brow weakness and a change in contour are uncommon, and they follow treatment at the wrong depth. The layer being treated sits near a small sensory nerve in some places and near a nerve that moves muscle or a compartment of fat in others, so the depth is an anatomical decision rather than a technical setting.
  • The surface is left intact, so there is no wound and no resurfacing effect. Pores, scars, pigment and creases etched into the skin are not changed, and nothing here removes skin or repositions a face that has descended.

When to Seek Care

  • A numb or tingling patch that is spreading rather than shrinking, or that is unchanged after several weeks.
  • Any weakness in the brow, any difficulty closing an eye, or a change in the shape of the face.
  • A blister, a burn or spreading redness at the surface, or pain that is worsening rather than settling.
  • Fever with warmth or discharge in the treated area — infection is uncommon because there is no wound, but it requires prompt assessment.

References & Further Reading

  • American Society of Plastic Surgeons (ASPS) — procedure and safety guidance
  • International Society of Aesthetic Plastic Surgery (ISAPS) — global aesthetic practice and safety guidance
  • National Institute for Health and Care Excellence (NICE, UK) — relevant guidance
  • Cochrane Library — systematic reviews
  • Chinese Medical Association Plastic Surgery Branch — clinical guidance

Medically reviewed by Tongchun Mao, MD (毛彤春), Deputy Director & Head of Aesthetic Surgery. Last reviewed: 19 September 2026.

This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.