Good evening. Mucositis
, which is the problem that you are experiencing, when it is associated with radiotherapy is not easy to solve. One thing that might calm you down is the knowledge that this is a temporary problem, which will resolve some days-weeks after stopping radiotherapy. For the time being, pain killers, local measures like lidocain in gel or swallows, oral sucralfate
, and the things you are already doing are correct. You should try to eat/drink thinks more soft and if you think you cannot eat, you should consult your doctor for a possible admission to the hospital.