Wound healing has nothing to do with blood type, so the recovery of a scratched face with blood type O is the same as that of a normal person, and not particularly fast. Different parts of the injury, different body types, different age groups of people healing speed is not the same. 1. When the wound is superficial, its healing is mainly through the growth of subcutaneous tissue and skin to cover the surface of the wound, at the same time, the healing process of the body to have enough nutrients and adequate blood supply, the flow of blood in the nutrients brought about at the same time take away the necrotic tissue, so the face of the wound than the body to heal faster. 2. Physical fitness: people with better physical fitness and stronger immunity have faster wound healing and vice versa. 3. Young people heal faster than older people due to better body functions and faster body metabolism.