The scenario you described is pretty much identical to my situation. Swollen lymph node, ultrasound confirmed several swollen nodes clumped on right side. 2 months later got CT with contrast. CT showed necrotic tissue in nodes. PCP ordered urgent biopsy and scope exam. ENT doctor confirmed tumor in right side of base of the tongue/tonsil and biopsy confirmed HPV 16 SCC, PET scan followed with no metastatic disease beyond throat area. Waiting for consultations with chemo and radio therapy oncologists for treatment plan. Trust in yourself and your doctors. They will get you through this.