After undergoing flap surgery for oral cancer, the surgical incision will generally need one to two months to reduce swelling. After the swelling has subsided, some sensation in the affected area will start to return. For patients with oral cancer, flap surgery is primarily conducted due to the extensive skin damage caused by radical excision of the cancer. Therefore, substitute surgery using a flap is necessary to ensure the postoperative appearance. However, after flap surgery, patients may experience some rejection reactions to the new flap, leading to swelling and redness at the site of the surgical incision. This condition generally subsides after anti-inflammatory treatment and natural absorption, typically within one to two months post-surgery.