Skin grafting is surgery to cover and repair wounds with a skin graft. A skin graft is a portion of healthy skin that is taken from another area of your body called the donor site. Substitute skin grafts may also be used. These grafts may be artificial or they may come from another person or animal, such as a pig. Substitute skin grafts may be used only as temporary covers when large areas of the skin are damaged. They are replaced with your own skin over time.