What should I do with the sores in my mouth from biting my cheek?

Find out why . The sores will probably heal and go away when you quit biting your cheek. See a dentist to determine why you are biting your cheek. It could be due to stress, your teeth not fitting together properly, or in rare cases due to a nerve problem. Until you can see a dentist, rinse with warm salt water or peroxyl mouthrinse.