Non acidic foods, and non spicy foods. Dairy products might actually be soothing. Like Ice cream or yogurt. Jello and pudding can be nice too. Or a nice smoothie or shake. Warm soup can be soothing. I suggest chicken soup.
Soup, bananas, applesauce, yogurt. Pretty much nothing that involves a lot of chewing and difficult to swallow. Dairy might be your best option. Hope this helped. A way to help with the soreness is to gargle salt water. Don't drink it! Pour salt into a glass of water and stir until it's dissolved. Gargle a mouthful of saltwater in your mouth for 15 seconds. Do this 2 more times. It will help with the irritation.