Your CT scan
does not show swellings but you have it on examination , if its so then it could be any allergic response
.As its difficult to understand that if you have swelling and the scan is not showing it.
You may ask other doctor to review the scan and get your self examined to or you can send us your neck photos and ct scan photos , we could help.
If its allergic response its serious and you must consult your doctor as soon as possible.