@dragonfire you had to make a decision on treatment and I believe you made the correct one. When surgical margins are not clear or lymphatic or vascular invasion is seen in histopath then this treatment would have been recommended on top of the surgery, as in my case. We also have learned the hard way that we don't know what questions to ask of our doctors regarding aftermath effects. It seems that not all of them give a complete list of adverse effects. I always suggest new patients question in detail all possible side effects and complications of treatments. But if we know how bad it can get, will we still choose what is likely the best treatment regimen being suggested for a cure?
I also use a humidifier beside the bed even now. I use Zylimelt tablets nightly to increase saliva production. Biotene rinse and gel are also helpful but I did not know about these when I had the mouth ulcers so I don't know if they would be uncomfortable with the ulceration. I have also found that a weak electrolyte drink is more hydrating than plain water and dehydration adds to our dry mouth at night.
When I finished my radiation and chemo and had a recheck at Mayo I was offered counseling for the depression that is frequently experienced at this stage of treatment. Perhaps your medical team can refer you to a therapist who specializes in cancer patients? There is an oral rinse called Magic Mouthwash that is mixed up by prescription that helps with pain and healing. so you can ask about that. It really takes a while to get past the fatigue though staying active can help. Just listen to your body and rest as needed. Do you have an animal shelter or humane society near you where you could volunteer to walk dogs a couple times a week? My new rescue dog who joined the family a month before my diagnosis was a huge help in keeping me active during healing. There was a lot of training to do and time spent outside with him was my best distraction. Be strong. Have hope. None of us chose this path but we can choose which one to take from here on. (Hope the Juven helps.)