aphthous stomatitis

"Aphthous stomatitis is when you get little sores or ulcers in your mouth that can be painful. It's like when you get a little cut on your finger, but it happens inside your mouth. It can happen if you accidentally bite your tongue or cheek, or if you have a lot of stress or not enough sleep. It's not contagious, which means you can't catch it from someone else like a cold or the flu. But it's important to take care of your mouth by eating healthy foods and brushing your teeth so the sores can heal and go away."