How to stop biting my tongue or the inside of my mouth when eating?

Chew slower: Sounds simple, but slow down. Once an area has trauma, it is swollen and becomes much easier to re-injure. Take your time and take it easy.

Biting: If you had recent dental treatment, it can cause the bite to be changed resulting in biting. Once it gets bitten then it gets swollen and you tend to bite more. I am not sure of your age but sleep apnea results in a lot of trauma to the oral cavity as well. Or as previously stated, slow down, let the bitten areas heal.