21 days ago I had fully protected sex with a girl I know, but not real well. I was looking around groin this morning just because I had been worried , found a small zit like bump on left side of scrotum. Couldn't see it real well but looked as if it had a head on it. I squeezed it and it seemed to pop..... Kind of. How do the cankers present ? Do they open right up and present as a full lesson?