Body Focused Repetitive Behavior - Cheek Biting is considered OCD 

I've dealt with cheek biting my whole life, but I wasn't aware until recently that it is actually under the spectrum of OCDs. If you have children who are cheek biting take them to a dentist. They have devices to break these types of habits, just like what they use to stop thumb sucking. Talk to your orthodontist if you are having severe problems.