Fluid accumulation under the skin one month after wound healing may be caused by infection under the scab, hematoma liquefaction, fat liquefaction and other factors. 1. infection under the scab: in the process of wound scabbing is not good care, resulting in infection inside the wound, infection aggravation will appear after the wound healing subcutaneous effusion. 2. hematoma liquefaction: if the wound suffered trauma patients with coagulation disorders, resulting in damage to the blood vessel wall, so that the blood from the blood vessels to the blood vessels outside the formation of subcutaneous hematoma, hematoma liquefaction will appear after the phenomenon of subcutaneous fluid accumulation. 3. Fat liquefaction: when the patient is obese, the capillaries in the adipose tissue at the wound are embolized due to thermal coagulation, and the fat is thicker to hinder the blood supply, aseptic necrosis is easy to occur, resulting in the healing of the epidermis and the accumulation of fluid under the skin. It is recommended that the patient should go to the hospital in time to treat the subcutaneous fluid in the wound, such as incision and drainage, puncture and suction. Do not delay the condition to avoid the impact on normal life.