Mouth ulcers on the tongue and inner parts of the mouth are common and are often caused by stress, lack of sleep, acidity, spicy foods, accidental biting, vitamin deficiencies, dehydration, or irritation from sharp teeth or braces. These ulcers can be painful while eating, drinking, or speaking, but many heal within 1-2 weeks with proper care. Try to avoid spicy, sour, salty, or very hot foods, as they can worsen irritation and pain. Drink plenty of water, maintain good oral hygiene, and use a soft toothbrush to avoid further injury to the mouth. Warm salt water rinses 2-3 times a day may help soothe the ulcers and keep the mouth clean. Applying ulcer gels may help reduce pain and support healing. Vitamin supplements containing vitamin B complex may also help if the ulcers are linked to nutritional deficiency. Proper sleep, stress reduction, and a healthy diet rich in fruits and vegetables may reduce the chances of ulcers recurring frequently. However, if the ulcers are very large, keep returning often, last more than 2 weeks, cause difficulty swallowing, or are associated with fever, weight loss, or swelling, you should consult a doctor or dentist for proper evaluation. Persistent or frequent ulcers may sometimes need further testing to identify the exact cause.