So,
I'm sure an internet search has turned up a number of possibilities, but let me echo what you have probably read many many times, GO SEE A DOCTOR! If you have any sort of infection or disease, the sooner you find out the better. And if it's nothing, the sooner you find out, the better as well.
As far as any shame or embarrassment, you are going to have to suck it up. Your health is more important. And if you take time to look at the society you live in, you will see that you have been socially constructed to feel shame about something like this. Look at it logically, there is nothing shameful about genitalia, it's just one of many parts of your body. And infections and abnormalities happen all the time to all parts of a persons body, so what if it has happened to your penis.
Do the right thing, get checked out.
D.
Please, tell me what to do before I make a stupid decision!