What Causes Swollen Glands In Neck And Behind The Ears?

I have 5 swollen glands on my neck right where it meets your chin. Both of the glands behind my ears are swollen, and one is swollen in the hinge of my left jaw. A little over a year ago I went to my doctor and she noticed that I had something that she later diagnosed as pitikia and ran blood work due to a history of AL Leukemia in my family. I am currently on Doxycycline for acne but have been on it for nearly a month. I am extremely worried. Any insight?