Hello Doc, I would be very grateful if you could read this and tell me in your opinion what the symptoms point to, My doctor didn't know. I'm getting tested & dont think its HSV, it doesn't look like it at all. Here goes...

6 days ago I noticed what looked like a large zit. I popped it like a zit and white puss came out. I wasn't too alarmed--I've had smaller zits in my pubic region. However this one was on the lower side of my penis, and a bit larger then the tiny zits I've had before. It bled a tiny bit more then I expected it too when popped, and healed a bit different--I monitored it healing closely and I'm almost sure it didn't scab. At this point it looks entirely healed but left a (?shinier), slightly raised light pink bump of skin where it was originally, it doesn't look like a scar to me. I have no other symptoms, and I don't remember it itching or hurting.
Here is a picture of the bump it left:
http://hidebehind.com/img/53/53077F.jpg

Could this be an std? Thanks,
J.E