What Causes An Ingrown Armpit Hair Mass With Pain And Body Pus?

my hubby noticed what he thought was an ingrown hair in his armpit the two days ago. Today it is the size of a golf ball and terribly painful. He is not prone to breakouts but he is getting pussy breakouts all over his body lately as well. In december he had his colon removed due to a bad case of ulcerative colitis. I am not sure if any of these new symptoms have anything to do with that or not, but i am just wondering what you think? He also has a large leaking pylonidal cyst in his rectal area do you think this is just the problem spreading or might it be something totally different