What could cause the lymph nodes in my neck and groin to be swollen for a month and little red bumps popping up everywhere?

HMM: It could be many things from infectious to metabolic...It definitely needs to be evaluated soon by a physician...See your family doc soon..Especially since you say that it is getting worse..

Monitoring Centers: Lymphatic system absorbs/carries things too big to go into the arteries/veins like bacteria eaten by white cells/digested food. Lymph nodes "taste" the lymph everywhere for bad stuff like bacteria/viruses/cancers, etc. When it detects a problem, it alerts the immune system and your body reacts. They enlarge in response to the inflammation they create when they react. They shrink when all is well.