How to treat a burnt tounge?

Topical & oral meds. A 'tongue burn' hurts 'like the dickens' but heals fast due to the generous blood supply. Treatment is supportive: topical pain meds (like anbesol) and tylenol (acetaminophen) can help.
Time. Fortunately the tongue heals remarkably fast. Cold water or ice cubes can make things feel better while your tongue is healing. Stick to soft bland foods. Avoid spicey and acidic foods and liquids as well as hot liquids. If your not better in a day or two see your dentist. There are ointments available but they are very difficult to keep on your tongue.