I'm wondering if it might just be the healing process as healing uses a lot of sugar too. Also if shes not HPV+ - and they suggest surgery again i would do it as this is the most effective way of treating this particular type of cancer - follow up with rads and chemo is also very much warranted - regardless I would say move FAST - this cancer can be very aggressive. Did she have perineural involvement? Did she have ECE (extra capular extension)? sometimes the cancer leaks outside the node so this could be the case of the neck. It's very possible it's a false positive but act as though it's not and push to have his dealt with immediely - no waiting for his appointment or that - make noise get some answers now. Please let us know what happens and best of luck.