The condition tends to start with a firm pea-sized lump that develops in 1 place. This will either disappear or rupture and ooze pus after a few hours or days.New lumps will then often develop in an area nearby. If these are not controlled with medicine, larger lumps may develop and spread. Narrow channels called sinus tracts also form under the skin that break out on the surface and leak pus.Hidradenitis suppurativa is very painful. The lumps develop on the skin in the following areas:around the groin and genitalsin the armpitson the bottom and around the anusbelow the breasts