Being head shy is normal. The simple thing to do about it is don't touch him on the head. Still easy to handle him without doing that. I find it weird people wanna force their snakes to get used to being touched on the head when it's not necessary to do so. Sure if you keep touching their head they can get used to it but there is no need and why would you wanna stress them out every time you do it until they realize it's ok?