STD? Itching/burning on penis

I am afraid that I might have an STD, but the symptoms I have don't seem to match anything that I've found while researching on the internet. On the shaft of my penis, just below the head, I have an itching and sometimes burning sensation. There may be some changes in what it looks like, but it's hard to tell. I don't see anything that looks like warts or a herpes rash as I've seen on the internet. There are two small bumps, a millimeter in diameter, a little bit whitish. Also, and I think this may be new, a line of raised skin almost like an old scar.

The itching gets worse worse as the day goes on, but a shower seems to relieve some of the sensation. Any ideas what it might be?

Thanks...