An additional aspect of “roll onto your chest” or “roll over onto your chest” implies you start on your back or your side so that when you roll your body, you are now lying with your chest toward the floor.

“Roll onto” is to move onto something “I rolled onto my chest” means I moved to be on my chest. “I rolled onto the floor” means I moved to be on the floor. Yes, you can say “Can you redo my hair” though “Can you fix my hair” is probably a bit more appropirate.