How long to swell after thyroid surgery depends on the healing of the patient’s incision and the different conditions of the patient. If the patient’s incision heals well after thyroid surgery and there is no subcutaneous fluid or blood accumulation, the swelling in the surgical area will be absorbed on its own within 2-3 days. If there is blood or fluid accumulation under the skin or even infection after thyroid surgery, the wound needs to be opened and drained as soon as possible and the incision needs to be changed as soon as possible, in which case the swelling in the surgical area often takes 5-7 days to recover. If there is nerve damage and dislodgement of the vascular ligature after thyroid surgery, it is necessary to go into the operating room again and perform local debridement treatment if necessary.