Yes, your doctor would definitely notice.
The lymph node behind the ear is one of the most sensitive lymph nodes and flares up for all sorts of reasons during this time of the year - fighting the flu, the cold, sinus infections, etc. So, it would still be normal even if you had nothing else going on, but considering that you've also been having issues with that ear, it's even more normal. When they flare up, that means they're doing their jobs. It could be swollen from having fought off an ear infection or is actively fighting germs because of the fluid, etc.
It can take a while for it to go back down, but if your doctor thought it was anything to worry about, he or she would have said so.