Sounds like a similar situation to mine. I just had both dissection and TORS done at the same time. When they did the PET scan (or any other tests) where they any positive finding of your tonsil or back of the tongue?

For me the only positive finding was that my right tonsil "lit up" a little more on the right than the left, but from what the radiologist interpreted and my readings online, that is not clinically significant. Negative CT scan for tonsil and tongue, and when I was scooped during surgery, no positive findings.

The biopsy of my right tonsil from surgery "negative for infiltrative carcinoma" and "Actinomyces" (sort of an inflammation)

So still unknown origin. Would be interesting to see what they find during your surgery.

Eating will be "difficult", just have to be creative on what you can eat, and yes, pain meds are helpful prior to eating. It does get better, at least for me it did.