What Causes Infected Cyst Formation In The Groin Area?

I m asking for my husband. He has been dealing with cyst/boil/pimple type skin issues for many years. In the last few months they have gotten larger and worse in general. He has a large one on the scrotum and another in close proximity in the groin area. He treated himself a few weeks back by taking oregano oil caplets orally. The discharge odor from the cysts diminished. However, now he explains that the cysts are becoming more solid/hard and seem to be growing rapidly in size.