Sorry to hear. Did they ever do a endoscope or pandendoscopy, wih biopsy, of the base of tongue, tonsil, and PET/CT scan being it's HPV positive? which type was it 16, 18, which 90% of the time is in the oropharyx or originated from there, and not the oral cavity, tongue, although the BOT can matastasuse to the anterior tongue. I agree with Cheryl regarding further treatment. Sometimes cancer is right outside the surgical margins, and not enough section wasn't removed, cancer comes back at the surgical incision sometimes, could be due to field of cancerization, usually with smoking, alcohol or other carcinigen related in the upper aerodegedtise tract can be involvef, and other reasons. Did that say it was a local regional recurrence with similar histology of the primary or a secondary or simultaneous cancer?

Good luck with everything.