Lump / pimple feeling on my right side?!

So I have what i thought was a pimple directly on my side above my hips, but if u feel it, it's more like a ball is inside or something. I tried popping it thinking it was a pimple, but it really hurts and when I popped it, blood just kept oozing out. I don't know if this is a really bad pimple (although I do seem to of had it for a long time now) or is there something I should be more concerned about?