Superficial skin damage caused by external friction, visible to the naked eye bleeding or oozing blood, oozing tissue fluid. For minor injuries and abrasions, after washing with normal saline, apply 20% mercuric chloride or 1% gentian violet (gentian violet cannot be applied to face to avoid pigmentation) or 2% tincture of iodine. The latter is reliable in disinfection, but the pain is obvious after application (not suitable for wounds over 0.5 square centimeters). If the scratch area is large or there are many foreign bodies such as mud and sand embedded, it should be thoroughly cleaned, which is not only necessary for disinfection, but also can avoid infection, scar and pigmentation caused by leaving foreign bodies. Therefore, debridement should be patient and carefully remove foreign bodies. If there is no physiological saline at the scene, it can also be washed with cold boiled water or even tap water, and then applied to the wound, including Yunnan Baiyao powder and antibiotic powder. Eat more high-protein foods in fruits and vegetables in the early stage to avoid spicy seafood. After scabbing, you can use drugs to promote scar softening, and you can go to the plastic surgery department to buy scar cream for external use. If the wound is fresh, recombinant epidermal growth factor can also be used to accelerate wound healing. If you don't hurt the dermis, you won't leave scars after healing.