Swelling may occur after removal of wisdom teeth, postoperative swelling reaction, usually due to the extraction of large trauma, appeared in the postoperative 12~24 hours, 3~5 days after the gradual subsidence of swelling, more soft and flexible, as follows. Swelling reaction after tooth extraction occurs when the trauma is large, especially after flap surgery, related to the trauma of flap turning, the incision of the flap is too low or suture is too tight, etc. It is easy to occur in the mandibular wisdom tooth extraction, which manifests itself as swelling in the front cheek. The swelling usually starts 12~24 hours after surgery and gradually subsides 3~5 days after surgery. The swelling is soft and elastic, and the skin can be pinched with the fingers. If the postoperative swelling is severe and continues without improvement, it is recommended to visit the hospital for early professional treatment.