Need help with layer or rigging situation

This is my character Charlie. He has trouble brushing the back of his throat with his toothbrush.

I layered/rigged him so that the toothbrush in Charelie's left hand is beneath some of the artwork of his mouth to demonstrate the toothbrush being inserted into his mouth. I have it so that it actually does look like he he brushing his teeth. Only issue is to make it work I had to layer certain face artwork outside of my +Head group, so now when it comes to recorded I'll have less visual effects, because he can't move his mouth artwork along with his head.

Any help, thanks in advice.