Is it harmful if I bite or chew on my cheek, tongue or lips? Yes, continued trauma and chronic irritation to your oral tissues can result in painful mouth sores or ulcers. Repeated trauma to these areas can also leave you susceptible to oral infections.
Research has found a possible link between mouth lesions and mouth cancer, especially those involving the tongue. The correct term for chronic cheek biting or chewing is called Morsicatio buccarum.

How to stop biting/chewing your cheeks, tongue or lips:

-see your dentist to check for positioning of teeth, malocclusion and jaw alignment
-pay attention to your habit, there may be a trigger (boredom, stress, anxiety)
-ask family or friends to help recognize when you are biting
-try chewing sugar-free gum or sucking on xylitol mints
-try relaxation methods such as deep breathing
-keep yourself active
-if anxiety issues persist, seeing a physician may help
-see your dentist or physician if a sore does not heal, constantly bleeds or causes difficulty with chewing or swallowing