as for the pain/burning in your mouth that comes from radiation, the fentanyl patch helps take away a lot of pain, but the baking soda, salt, and water rinses they tell you to use helps with pain and the saliva.
Your saliva will get very thick, but staying hydrated helps a bit with that, nights are toughest as you can't drink when you are sleeping and it seems to like to sit at the back of your throat.
I am a month and a half out of radiation and my saliva is a lot more manageable but still kinda thick. There are meds they can give you to help with the thickness of the saliva, but my docs said they don't really help, so I am not sure about those.
I wish you luck with all of this and once you get through radiation a few weeks after you will feel a bit better and slowly but surely you will get to feeling better.
I am energy wise back to where I was before almost and my mouth sores are still there, but they don't hurt as much. Now I just have to build my muscles back up as they decreased and shrank from being in bed for 4.5 months.

Best wishes and sooner then you know it you will be done with radiation and on the road to recovery!