The common causes of pain when pressing the scab 1 month after flap surgery include incomplete healing of the surgical opening, infection, scar hyperplasia, and thread reaction. 1. Incomplete healing of the surgical opening: for some serious underlying diseases, such as chronic renal failure, diabetes, vascular occlusion, etc., because of poor nutrition and poor blood circulation, will affect the recovery of the surgical opening. 2. Infection: The wound is not well taken care of after the operation or the bacteria spreads to the surgical opening through the blood, which causes infection and leads to non-healing of the surgical opening. 3. Keloid hyperplasia: For people with keloid body, because of keloid hyperplasia, it can also lead to pain and discomfort at the operation opening. There are many reasons for postoperative flap pressure pain, and it may also be related to the reaction of the thread knot, not quitting smoking after surgery, etc. If the symptoms continue to be unrelieved, it is recommended to consult a doctor in time to clarify the cause of the disease, and carry out targeted treatment.