20 years old scars, generally due to poor healing caused by trauma, can be treated by laser therapy, surgical treatment and other ways. 1. Laser therapy: raised scars can be treated with pulsed dye laser and fractional laser. Fractional laser with stripping effect is preferred, which can strip the surface tissues and promote collagen fiber regeneration, which can improve the appearance of scars. 2. Surgery: It is suitable for large scars, depressed scars and keloid scars, and the old scars can be removed through surgery and then sutured with reduced tension, and the appearance of scars and uncomfortable symptoms can be improved through the use of scar inhibiting drugs and sunscreen after the surgery. The above treatments should be carried out under the supervision of a physician. If the patient needs treatment for old scars, please go to the hospital for consultation.