Finger caught in the door after the nail loss, the nail can grow back, with the degree of external damage, generally if the nail bed and the nail matrix is not damaged, the nail can be regenerated. The nail matrix is located at the root of the nail, as a special epithelial tissue, the nail is produced by the nail cell chemotaxis. Therefore, if the nail is damaged by external force, its keratinization may be affected, resulting in failure to regrow the nail. The nail bed is located in the deep surface of the nail, a special layer of epidermal tissue, connecting the nail and the skin, such as the place of injury, can lead to separation of the nail and the skin, affecting the normal growth of the nail. If your finger is pinched by a door, you should go to the hospital promptly to avoid further infection of the affected area and damage to the nail bed and nail matrix, resulting in failure of nail regrowth.