Wax it!?
What is the best way to shave your head, other than razors which damage the skin?
You can get pretty close with a clipper. It won't be as close as a razor though.
They do make some electric shavers now that are just for your head. A couple of these look like they'll do the job just fine. Specialty electric razors !
Top 5 Best Electric Head Shaver List For Men 2015 - 2016
A razor only damages it if you're shaving wrong