Sounds like an allergic reaction
Have you changed washing powder or soap or deodorant recently?
Have you stayed in a motel/hotel/b&b recently?
Have you stayed outdoors or gone hiking?
Lymph nodes can/do swell when there is strain on the immune system, which in your case there is as your body is clearly fighting something.
This is one of those times when you really really need to go see your doctor. If it is an allergy he can give you something to help, if it is something else he can make a diagnosis or take a skin scraping (not as painful as it sounds) to send to the lab for analysis.
Either way, this doesn't sound like something you can or should ignore.