@opeggisu1 Welcome to Mayo Clinic Connect! I’m so sorry that a miserable condition brought you here. I posted an item from Cleveland Clinic that has some helpful things you can do at home for your mucositis.
https://my.clevelandclinic.org/health/diseases/24181-mucositis
I remember when I got mucositis after getting chemo. Wow, my mouth hurt! But I remembered the salt and soda rinse from my days as a cancer nurse. Take a cupful of clean water (you can use sterile or bottled water from the store) and stir in equal part of salt and soda. Then rinse your mouth carefully. Do this 4-6 times a day. If you read through all of the discussion, you will find quite a few self-help tips.
Did the dentist give you any idea of where the mucositis came from?