I feel for you, Julie. Mucositis is the pits.
My wife survived on popsicles during the worst of it. She also had a device, kind of like dentists use, that let her syphon saliva out of her mouth rather than having to swallow it, because swallowing was painful. That really helped her.
Don't let them short-change you on the pain medication. Keeping on top of pain can help your overall recovery because you won't spend all of your energy gritting your teeth against pain.