Welcome! It happened to me too with the PET/CT scan, even at testing at 5 months post treatment, and needed an MRI with contrast, which was also inconclusive due to dental filling scatter, and then had an FNAB. Tonsils are known to highly reactive due to the high lymphatic activity there, as well as others. You had stage 1, early stage, was
HPV positive, and both respond well to treatment, so that is very good. Try not to worry, which is easier said then done. Happy New Year, and good luck with the next scan.