so it started off as a small red bump, it wasn't sore at first but it became really irritated and red. I woke up the next morning and it looked like a pimple on my penile shaft and when I tried to pop it, it didn't budge. it then became really dark coloured, black and dark red and then ended up popping and leaking yellow/green/pink gunky puss. at the base of the sore it feels like a small mass around a centimetre and a half under the skin itself and after it popped, the blackness and redness seemed to go into my skin causing a slight hole/indent
Go get checked and treated as soon as you can, did it appeared after a sexual activity ? if yes it could be Syphilis bro