Get the fluoride trays, prescription fluoride! I didn't, for a few reasons, one my dentist didn't recommend them, and I went with the flow, being I didn't want any medications that can cause illness after being in the hospital 187 days. Now ALL my teeth need to be extracted two years after radiation, a 2nd course of HBOT with 30 dives, and this is sometime after my neck dissection, and radiation next month. I currently have a gum infection, abscess, in the jaw line, which can compomise having my surgery. I'm taking strong antibiotics 3x a day, which risks c-diff, and I'm more susceptible since I had it before, and that can kill you, besides infections going septic.

Cancer could be in the other nodes, and not detectable, could be skip metastases or biopsy didn't get a good sample slide with cancer. They are going to radiate from your top lip, down to your shoulders. There are over 300 lymph nodes in the head and neck, most microscopic, so I don't think they get them all out, and every one of the three neck dissection I had, two radical. always had more to remove. Lymph involement further down the lymph chain has its own prognostic factors, after that V, maybe lungs, but cancer can go anywhere. Mine started in II, and then III, IV, V, and was in the skin, neck muscle, and it may be good you had the neck dissection, but would think they would do chemo too, HPV or not, since there are no guarantees how it will behave, and some HPV are aggressive, acting like tobacco caused cancer.

Good luck.