Ultrasonic knife is a kind of focused ultrasound, clinically used mostly in skin beauty, the use of ultrasound in biological tissues, such as directionality, penetrability and focusability and other physical properties, the use of ultrasonic knife in the subcutaneous caused by mild scarring, the use of scarring itself contracture, to enhance the purpose of the facial tissues. However, if the medical staff does not strictly comply with the norms of the surgical process, the following complications may occur: 1. Although anesthetic cream will be applied during the surgery, it only acts on the surface layer of the skin, while ultrasonic knife treatment acts on the depth of the skin, and during the treatment period, the candidate may feel pain in the local skin or subcutaneous; 2. If the skin is seriously lacking in collagen and hyaluronic acid, it may result in mild scars, and the ultrasonic knife is prone to causing the The phenomenon of damage to the bottom of the dermis, so that the facial substrate is destroyed, skin nutrition is not balanced, thus causing skin unevenness, or even permanent collapse, uneven skin color and other side effects; 3, high-temperature focused electric shock process, will evaporate a large amount of subcutaneous water, resulting in abnormal dry skin, dry, dull, raw spots and other phenomena; 4, in the ultrasonic knife process, if the radio frequency probe stays for too long or the temperature is too high, the Cause subcutaneous tissue burning, redness, swelling, blistering, necrosis and other phenomena.