Hair transplant surgery is normally safe when performed by a qualified, experienced board-certified plastic surgeon. Still, individuals vary greatly in their physical reactions and healing abilities, and the outcome is never completely predictable. As in any surgical procedure, the infection may occur.
Some side effects include:
-bleeding at the transplant area
-swelling of the scalp.
-bruising around the eyes.
-a crust that forms on the areas of the scalp where hair was removed or implanted.
-numbness or lack of sensation on the treated areas of the scalp.
-inflammation or infection of the hair follicles, which is known as folliculiti
-visible areas of hair that don’t match the surrounding hair or are noticeably thinner

Hair transplants are typically more successful than over-the-counter hair restoration products. But there are some factors to consider: Anywhere from 10 to 80 percent of transplanted hair will fully grow back in an estimated three to four months. Like regular hair, transplanted hair will thin over time.