After an anal fissure is removed the wound heals slowly and new skin gradually grows. Anal fissures are small ulcers that form when the skin below the dentate line splits, and most fissures are located in the posterior midline of the anal canal. The cause of anal fissure is not yet fully understood. For anal fissures that do not heal for a long time and for which conservative treatments are ineffective, surgical treatments are available, and the wounds will heal slowly after anal fissure excision and new skin will gradually grow. Fissure resection is a common surgical procedure to treat anal fissure. During the operation, all the hardened anal fissure margins, anterior hemorrhoids, anal papillae and other unhealthy tissues are removed until the anal sphincter is exposed, and the wound is left open for drainage. Afterwards, the wound will heal slowly, new granulation tissue grows to fill in the defect, and new epidermal skin will cover the top to form a new skin. After surgery, the wound is protected with regular dressing changes until it heals.