(No, no, not those cheek
A habit similar to nail biting (onychophagia) in which one bites the inside surface of one's cheeks or lips. This can happen during sleep, as a result of bruxism (teeth-grinding). It can also happen more or less unconsciously during the day, as a compulsive habit.
I was a daytime cheek-biter for about 15 years, starting in my mid-20s. I wanted to stop, but I always succumbed to the urge to chew. Any little rough spot on the inside of my cheek would make me want to bite it off, and they were always rough because I was always chewing on them. About a year ago, I simply stopped. This coincided with a big change in my life: divorce. Who knows what's going on there! Since then, the inside of my mouth is smooth and without sore spots.
I never sought professional help for this problem. It might belong to a spectrum of OCD-like behaviors. Like onychophagia (nail-biting), trichotillomania (hair-pulling) and other repetitive grooming impulses, there is evidence that treatment with SSRIs can help people resist the urge when this behavior gets out of hand.