Be forewarned that the radiation side effects will continue for several weeks after "beam off" (and can actually get worse). The mucositus will be a problem and others have already mentioned pain management and nutrition. It is vital to stay hydrated and also take aggressive steps to mitigate constipation, which is caused by the pain meds.

Personally I had Fentanyl, 72 hour time release patch with Morphine for breakthrough pain (Morphine is the fastest acting oral pain relief). Pain management was critical in the timeframe of post Tx - but so was constipation management. You will want to have ongoing consults with the nutritionist about that. For many of us it was the WORST part of recovery. I spent many hours curled up in a fetal position by the toilet.

My trick was to take a few Morphine tablets, swish and spit with Pink Magic then I had about 30 or so minutes to eat and drink. A feeding tube probably would have made life a lot easier...