People usually bite themselves while eating because of careless or preoccupied chewing, according to Thomas P. Connelly, D.D.S. For example, talking or reading while eating distracts people from chewing, which can result in them biting themselves.
Distracted chewing is the primary cause of people biting themselves while chewing, and it happens occasionally to most people, according to Thomas P. Connelly, D.D.S., writing in the Huffington Post. Another reason this happens is due to misalignment of teeth, which causes more chronic, consistent tongue or cheek biting. Misalignment occurs when permanent teeth don't line up properly because of missing teeth, as a result of a joint disorder or because of false teeth that are improperly aligned. Cheek biting as a result of misaligned teeth can lead to chronic cheek biting, which has the potential to become a nervous habit.
Thomas P. Connelly, D.D.S. points out that there are several fixes for this problem, starting with slower, more careful food chewing. If the cause of biting the cheek while chewing is misaligned teeth, then that needs to be corrected through dental work. If cheek biting has reached a level of becoming habit, then a person can chew gum or wear some sort of lip balm to discourage the cheek biting. This is a habit that needs to be stopped because it causes sores and legions in the mouth that are not only painful but also at a risk of infection.