Once the skull dries just epoxy the teeth back in. That happens sometimes,

You can either bury the skull in an anthill or boil it. If you boil it, don't overboil. I have two bear skulls that I boiled; one was a bit overdone and the teeth fell out.

After boiling, you can bleach it if you want.

What do you use to bleach it? I use peroxide and have had good results