I had this wierd black mark under my belly above my left leg which looked like a pimple, and it was there from many years I don't remember, what happened was that i decided to peel it out. I used a compass which i don't think was rusted and tried to peel it off, a little while later blood started coming out and i stopped. About a week later it had become a little reddish around and swollen a little bit, and it pains if i press on it. I took a tetanus shot around 1.5 years ago what do i do?