@justwow Hello . First off this a very winnable battle. In particular, if this is HPV +16 as you stated. Google can certainly take you down the rabbit hole with negative outcomes. Your odds are extremely good ! HPV 16 Cancer recurrence is less than 20% in most studies.
If this is any help here is my story which is very close to your current situation....I am 58. I was diagnosed with Stage 4 HPV 16+cancer of Base of tongue and Neck March 2023. I had TORS(robotic) surgery April 2023 to remove base of tongue 3cm tumor ( partial glossectomy )and lymph nodes through right neck dissection. 2 of which had cancer. I opted out of any Chemo treatment. I chose Proton vs Photon Radiation as I feel it is much less damaging . In my opinion Proton is more targeted with less side effects. However, It is a battle as insurance companies do not want to pay for Proton when Photon is 50% less costly or more. Proton is like a pencil beam hitting the target and stopping. Photon is more like a flashlight beam which travels through the target area. I had to drive an hour to Proton treatment. Alot of people drive much further. I had 30 rounds ( ending July 2023) of Proton Radiation to "cleanup" any cancer that may have been left behind from HPV16 base of tongue and Few Lymph nodes . l was very worried about going on a feed tubing , Dysphagia and Not being about to swallow (eat or drink). I started doing mouth, Neck, tongue and swallowing exercises prior to proton Radiation. You may need to seek a Speech therapist as they can help with this. It was a struggle to eat during radiation and I FORCED myself. You will lose appetite and everything will have no taste. Now the good news... As far as today two years out. I can eat and drink about anything I want. My taste buds are about 95% , My throat mucositis has almost gone away, Saliva production 95% and My stamina is back to about 95% . I have no issues with speaking, eating, moving my mouth or raising my arms as you mentioned you were worried about. I will continue to have a throat scope and CT scan every 6 months for two more years or so. So far no evidence of cancer remains. You should also ask about the NavDx Blood test for HPV 16. It will become more important once you have completed your treatment to monitor any HPV 16 cancer activity in your system. My NavDx blood work continues to show no sign of cancer.
Make no mistake this will not be a fun 6 months or so. However, You will make it and things in a year will be looking up. Some things may not taste the same, some slight neck or throat discomfort but you will be alive. There will be a new "normal" but It beats the alternative. Lean on your Faith