The top of Mojo's head turned almost all white too when he was little...it isn't white anymore, of course...but I wondered about it at first.
Good luck with the groomer....will you stay while he is groomed?
If you need help with home grooming, you can check out the grooming section
HERE or just ask. Most of us to a lot of grooming and cleanings ourselves at home. - makes it more comfortable for the babies and us mommies too!