So im 18 and ive been sexually active with a few girls. I have developed a red bump on scrotum and i'm not sure what it is from. It has popped and was filled with pus. But that was about 9 months ago. It is a very faint bump and i'm not sure what to think of it because it has been there for so long and no longer fills with any white substance it just lays there seemingly dormant. Sometimes it seems to start to go away and then it never does. Should i worry? What could this be