My midwife suggested this after a tooth extraction.
Us Irish have different blood/body chemistry. Many of us are allergic/sensitive to foods high in vitamin C, like tomatoes and oranges. These things CAUSE canker sores for us, believe it or not. I have a lot of irish blood, and I recently got my tooth pulled. I have stitches in my mouth, and here is what works for relieving the pain:
fresh comfrey tea leaves put in a small tea bag, put tea bag in warm water (about 1/4 cup) until a tea forms. Rub the tea bag until the outside kind of feels slippery or oily, similar to aloe vera. Hold the tea bag over the sore.
Hold until pain subsides, or bite down on bag instead of gauze as dentist suggests after extraction. Research Comfrey Root and leaves for more information on uses.
Also drink Throat Coat tea (gypsy cold cure in your grocery store aisle) with black licorice in it for swelling, and rinse mouth with Tom's baking soda and witch hazel mouthwash to keep wounds bacteria free. Follow with a tepid salt water gargle and gentle spit.
This is a good "Ora-gel" for very sensitive skin/people. It won't work for people who have a high tolerence to over the counter drugs. Less Sensitive individuals would need aloe mixed with Ora-gel, and to go the gargle with Green Tea/Orange Juice route.