I'd alert your team to the possibility that the primary tumor (which, as I read it, they have been unable to find) is located in the base of your tongue.
I went through a 60 day delay myself because they were unable to locate my own primary, which as you may have guessed, was in the base of my tongue.
CT scans did not show it, but the PET did. Perhaps they might run a PET on you with emphasis on that area (BoT).
If your cancer is
HPV related, it is probably very slow acting and has not spread appreciably since your diagnosis.
Question: Is your state a Medical Marijuana state? If it is, I'd also recommend getting a card ASAP. Cisplatin will introduce you to nausea.
Other than that, I echo everything ChristineB said.