I Had One Patch Of Smooth Skin Missing From My

I had one patch of smooth skin missing from my penis about half in in diameter missing. Looks like the first layer of skin was gone. In addition I had two red bump about 2 mm's in diameter that appear under the skin. The red bumps grew upwards and eventually popped. After 5 days new skin had completely covered all three wounds. I noticed this a few hours after a shower and vigorous masturbation. I'm worried it could be an std.