I had a big pimple on butt cheek few years back which got cured after taking medicines. Now at the same place I have found a hard painless lump inside the skin, which I can feel only on pressing the area with my fingers not while sitting or doing anything. When I smell my fingers after touching the area it's smells bad. The area is not near the anus but almost at the center of butt cheek. I am not getting what is this.