There is a bulging hard lump after the wound is good, because after the local tissue is damaged, the local tissue occurs fibrous repair formation of scar tissue, scar tissue protrudes from the surface of the skin, because the touch seems like a bulging lump. When the skin tissue is damaged, at the same time, the damage to the local parenchymal cells and mesenchymal cells proliferation, play these cells repair function. At the same time the larger part of the defect will form granulation tissue. Through the growth of the granulation tissue, it will gradually turn into collagen fiber-based scar tissue to complete the repair. In this way, scar tissue is created in the wound and healing occurs gradually. Scar tissue helps to maintain the integrity of the skin by connecting the skin to the wound, and the large number of collagen fibers has a certain resistance to pressure and damage. However, the proliferation and repair of keloid tissue may be overgrown, and may even form keloid bumps and bulging hard lumps. Therefore, if the patient’s injured skin mass is too large and has not been reduced, it is recommended to immediately consult a doctor and follow the doctor’s instructions for treatment.