I have had a nevus sebaceous birthmark removed from my head, causing hair loss around the wound. Is this normal? (photo)

Surgery on the scalp can result in increased tension in your four head. This can may lead to transient or even permanent hair loss in certain instances.Given your timing, it is too early to tell if it will return or not. If it does not return, then hair transplantation into the thinning areas would be a very good option for you. I would wait a good 6 to 12 months before endeavoring any additional options.

With any surgery to the scalp, some hair loss will occur. Whether there will be an area of permanent hair loss is not possible to tell. It's a good idea to let the area heal and any hair that was just temporarily injured will grow back. Some hair in any surgery has the potential to be permanent injured and such hair will not grow back. You won't be able to tell how much of each you have for 6-9 months.

The wound that I see is worry-some so I would go back and see your surgeon and ask your surgeon to examine it and render an opinion