Blood blisters in the mouth from eating may be caused by bite trauma, burns, choking injuries, hemangiomas, allergies, etc. It is recommended to go to the hospital for timely examination and treatment. 1. Eating too quickly or biting too fast will surely bite inadvertently resulting in trauma to the mouth and blood blisters, sometimes forming mucous gland cysts. 2. Scalding blood blisters may occur when eating overheated food, which should be allowed to air dry before eating. 3. Larger, harder foods may pinch the mouth while eating. 4. If there is a hemangioma on the mouth, the hemangioma may increase in size and look like a blood blister when eating food due to lip movement. 5. It may also be caused by allergies.