Bethesda,
Have you discussed this with your doctors like ENT, radiation and medical oncologists? What did they say and gonna do? It’s also where you received the most radiation at the original site? I know after radiation there can be an inflammatory response and or dead tissue. What my radiation oncologist did for me was to monitor the site, and I didn’t go for a PET scan until the 5 month mark. Some may do a scan at the usual 3 months. The can do a scan eatkier, but depending on when there still could be swelling, and show a false positive.
If you haven’t already, discus your concerns with your doctors! Good luck!