Sore Throat and Canker Sore Remedy: First apply peroxide directly on the sore with a q-tip. Let it do its magic for a minute. Rinse mouth. Then Mix 1tbsp of each Pepto-Bismol and liquid Benedryl. Apply with a q-tip to the canker sore twice. Rub the sore with some force if you can tolerate. Use remaining solution to swish in your mouth, making sure to cover the area with the sore. Spit out and wait 5 minutes before rinsing if needed. Do 4-5 times a day. Supposedly works great..