i'm not a user on this board nor have i used these so i don't know how this works but i found a large zit like bump on the shaft of my penis and at the top of this thing that looks like a zit is a purple or black head to it i'm really freaked out. I have a gf and we have been together but we were each others firsts and i'm not really sure how it can be STD related but it's scarin me. I have looked into all today and have an app. tomorrow. Any ideas on what this might be?