Pain from an ulcer on your tonsil is probably caused by something you ate or drank. Food allergies and highly acidic foods can cause canker sores to form in this region of your oral cavity, as your tonsils come in contact with these irritants when you swallow.

What does an ulcer on my tonsil mean?

There are numerous causes for these ulcers, including infections, viruses including herpes and HPV, autoimmune diseases, vitamin and nutritional deficiencies, acid reflux, allergies, reactions to certain foods, excessive coughing, excessive vomiting, oral trauma, stress, cancer, and chemotherapy.

How long do canker sores last on tonsil?

If you have a small ulcer on your tonsil, you can expect the soreness to reduce in 2-3 days and disappear fully with 7-10 days. However, for large canker sores, 4 weeks is the minimum time required for healing. Once your bump heals, it may leave a spot on the back of your throat.