Hi Lisa, hope you are holding up ok.
Dave is on his third week of radiation and going for his second chemo on Monday so I think we are close to where you and Ken are.
The team at Sloan recommends rinsing your mouth every 4-6 hours with some variation of the baking soda solution.
They also recommend a humidifer especially at night

For skin care, they suggest that he use Aquaphor or Eucerin twice a day. Right after the treatment and at night. That stuff is very thick.

You could also ask the nurse about sprays like Cepacol. It provides temporary relief.