Hair can be regenerated. Even if the hair is lost, the hair follicles below the scalp tissue are still healthy and will continue to grow hair. In some cases of alopecia, such as baldness, even if a large piece of hair is lost, the hair follicles below the scalp will gradually grow some hairs, which will eventually grow out of the scalp and form new hair. In some cases, even if there are fewer hair follicles in the hair loss area, or even if they disappear, the hair can regrow because the hair matrices below the skin tissue produce a certain proliferative reaction or change to produce hair follicles, and new hair growth will also occur, so the hair can regenerate.