Have you gone to the doctor to have this checked? I get shaving irritations under my arms, but it is not a lump. Always good to get something like this checked out if you have had it for a while and it is not going away. Keep us updated. I know what helped me with cysts on my breasts was cutting out coffee. For some reason the caffeine just irritated them.
If the lump is hard like a marble - then get it checked asap.
Eternalsummersong did you go to the doctor, was curious if you had any news on this, let us know, was thinking about you :D
It had turned into a very painful boil which did indeed have a cyst in it. They lanced it....one question why did he need a tea bag? I didn't exactly see what he did I'm squeamish when it comes to popping boils.