In daily life, people inevitably suffer from various injuries, such as trauma of different degrees due to burns, cuts, trauma, surgical infection, etc. The healing process of trauma is completed in the form of scar formation, that is to say, the repair process of various traumas heals in the form of scar, therefore, the healing of trauma and scar formation is a series process with inseparable cause-and-effect relationship. Usually, after scar formation, there is no scar proliferation or only slight scar proliferation and then immediately decreases, matures and rests. A few scars can experience several months, six months, one year or even longer, and finally flat, soft and close to normal skin. These are referred to as normal keloids. Very few keloids are prolonged, significantly higher than the skin surface, and have a reddish-brown color, hard texture, itchy, painful or tight feeling, some keloids even erode the normal skin, contracture deformity, or repeatedly break down and affect the normal function of the local area, these keloids usually need treatment. 1.Flat scar: basically flush with the surrounding skin, flat and shiny surface, no normal skin structure and texture such as pores, local skin color becomes lighter or darker, no uncomfortable feeling and functional disorder. 2. Superficial scar: rough surface, local skin with color change, often involving only aesthetic problems, without functional disorders and discomfort. 3.Deep scar: A scar that occurs under the skin and its deeper tissues. When the damage is small, it usually does not affect the appearance and function. When the damage is extensive, it can lead to skin displacement, organ deformation or ectropion due to pulling. 4. Atrophic scar: flat and thin surface, easy to break down after friction, darkening or lightening of scar skin color and hardening of texture. There is usually no discomfort and it does not affect the local function. 5.Depressed scar: scar lower than normal skin, local skin may have color change, does not affect function, and there is no obvious discomfort. 6.Linear scar: narrow strip, local color may be different from the surrounding skin, mostly without discomfort and functional impairment. 7.Webbed scar: It occurs in the area across the joint or around the open organ, with a flat or atrophic scar surface. 8. Superfluous and bridged scar: The scar is shaped like a superfluous or bridged skin with a flat surface. 9.Contracture scar: The scar is deep and thick, with a large scope, contracting or proliferating by itself, causing local functional impairment. 10.Unstable scar: Most of them are contracture scar, because of the local thinness and poor blood flow, they often break down in the friction-prone area, repeatedly break down or form ulcers for a long time. 11. Painful scar: scar with obvious pain and tenderness during or after the proliferative period. 12.Proliferative scar: higher than normal skin with uneven surface, visible capillary expansion, red or purple color, hard texture, itchy and painful. 13.Keloid scar: The appearance and symptoms are extremely similar to proliferative keloid scar, but it keeps increasing in size after eroding the normal skin.