A hard knot on the C-section incision scar may be caused by too tight knotting of the subcutaneous tissue, infection, fat liquefaction and so on. 1. During the cesarean section, the doctor knots the subcutaneous tissue too tightly, or the patient’s subcutaneous fat layer is thick. After tying the knot, the fat layer is squeezed and accumulated, and there is a hard knot in the incision. Generally, this kind of hard knot does not need special treatment, as the sutures are absorbed, the hard knot will gradually dissipate. 2. Infection. This kind of nodule often has pressure pain, and the epidermis will be red, some skin temperature will rise. If infection occurs, the wound must be treated actively to avoid its deterioration. 3. Fat liquefaction. In some cases, during the initial stages of fat liquefaction, oily fluid does not seep out of the wound and accumulates within the wound to form a lump. This condition should also be treated aggressively. The wound can heal only if the oily secretions are drained. In the event of abnormalities in the cesarean section wound, it is recommended to seek medical attention, follow the doctor’s instructions for further examination, clarify the cause with the help of the doctor, and carry out targeted treatment or therapy.