I am not a doctor but I am a cancer patient with a lot of CT Scan experience.
Doctors don't usually take a lymph node out unless they have too but they do take a biopsy from it. I have had two biospys in my neck nodes and the second time they removed it because of how small it was and the location.
Did they inject you with iodine or have you drink barium?
If you learn that they did see something suspect for cancer then if it were me I would want a PET Scan. A lot of times they won't request a PET scan until they have confirmed it is cancer. I think one reason for this is the cost of the PET scan, insurance companies will pay for it but they must have requirements.
For your on peace of mind and the simple fact of staying healthy I would suggest you stay on the doctors unitl they can tell you why the nodes have not gone down.
BTW: Both times I have been diagnosed with cancer my blood work was perfect.