Biopsy for sure, in my opinion. I lost a year to questionable diagnosis until one ENT specialist decided to do one. Now, I did have a swelling in my neck which was easier to biopsy and those results led to back of tongue HPV. I wish the three MDs before him had reasoned it out and done the biopsy. Hope you find some rest from the unknown.

Age 55 HPV 16+ SCC, BOT 050613 Stage IV
great team at OSU
Tx 6 weeks of rad started June 3
8 weeks of chemo started May 28
RTOG Phase III trial Cetuximab group.
Treatment completed 7/16/2013
PET Scan completed 10/08/13
Results discussed 10/11/13
NED - Free but am I
Next part of the journey?
1year PET 10/24/14 NED
Good reports now 10 years out.