where are canker sores in the mouth on palate
What are canker sores? Canker sores (also called aphthous ulcers) are different than fever blisters. They are small, red or white, shallow ulcers occurring on the tongue, soft palate, or inside the lips and cheeks; they do not occur in the roof of the mouth or the gums. They are quite painful, and usually last 5-10 days.