Hi Trappitt1 I had surgery to remove a tumour in my gum and jaw last year, followed by 6 weeks of daily Radiotherapy whilst wearing the full faced mask.  I guess you have one whilst they give you the treatment. In my experience drinking lots of high protein home made shakes helped me to keep energy and helped with the healing process.  I used fruits, yoghurt,  porridge, skimmed milk powder, almonds, full fat milk. Anything really high in calories. Even ice cream.  I am not sure what side effects you are experiencing but they do build up as the treatment progresses but  although the medical team tell you All the worst possible ones, you may be lucky and not expierence too many.  Let me know if I can give you any more help. Try and keep eating and drinking.