About a month ago a pimple appeared on the shaft of my penis. Stupidly enough i popped it and didn't treat it very well so i'm pretty sure it got infected, as a small blister appeared next to where the pimple was and pus was coming out. Eventually after treating it with anticeptic cream the blister dissapeared and it healed over, but now there is a scar left there. When flaccid it's a really dark, like almost black but when erect it is non existant. Is it just a regular scar, should i be worried about it? Also around the time the pimple appeared i wasn;t sexually active.