Ultrasonic scalpel, i.e. focused ultrasound and micro-focused ultrasound, is a form of ultrasound energy focused on a certain area, which usually acts on the dermal layer of the skin or the subcutaneous fascia layer. However, due to the deeper action and higher intensity, it is inevitable that there will be a certain amount of pain during the treatment. Patients who are afraid of pain can be relieved by applying anesthetic externally, but individual candidates cannot be relieved by applying anesthetic externally. Therefore, during the treatment process, some candidates may feel burning pain, accompanied by numbness, which is generally tolerable.