Anything is possible, but maybe not probable with all these clear tests, minus the hyoid bone. I would think at 3 weeks there still may be pain. I probably had 26 or so scans, FNAB, and none proved inaccurate, except for one MRI, just did't see the cancet, but was baked up by doing a PET/CT. Uptake can be from anything, and is not solely relied on for diagnosis. Yes, the BOT has deep musculature, and can go deep, being undetectable by palpable exam, but would think one of the other scans would pick it up too.
I hope you find answers, and it's not cancer until proven otherwise. Good luck.