About 4 days ago I noticed a large bump on my penis. I just waited to see if it would go away. Now though, it is pretty large (about 1.5cm long, 1cm 0.5cm across) and puss has began coming out. I squeezed it and it started bleeding a little. It was painful at first but not anymore. It's not an STD or anything. I'm not really worried about it because I've had something like this before but it didn't last as long as this time. Any idea would it could be and how long it will last?