Is it safe to gargle with some hydrogen peroxide and water?
Under normal conditions gargling with Hydrogen Peroxide would be a safe oral cleaning agent, BUT because your mouth is already infected and raw I do not recommend it. The mouth uses a delicate balance of good bacteria and bad just like other parts of the body. If you use to much of a cleaning agent you could end up with thrush. If you are looking for relief try a NON-Alcohol based Anti-Bacterial mouthwash which is sold at most drug stores for about 6-12 dollars. Gargle with this around 3-4 times a day especially after meals. If you are still not seeing relief, I would go see an ENT ( Ear, Nose, and Throat) specialist. Also look at something called Gentle Violet it is sold at the drug store and it taste horrible but it does help. Yogurt is also a good way to restore pro-biotic bacteria to the mouth and body. Try a warm washcloth on your glands to help reduce the pain.