HELP small red/purple shiny bump on penis

[xoddus245]

A week ago, I found a tender bump on the shaft of my penis.  It was hard, but had a tiny white head, which I was able to squeeze out.  The next day, the bump had become a hard, red, round bump on the surface of the skin.  I applied rubbing alcohol and neosporin, and waited for it to subside.

It has been a week, and now I notice it has slightly grown in size from a round bump, to an oblong one -- 1/5cm wide by 1/3 cm long.  It does not hurt, is hard, and appears to be under the surface of the skin, although it moves with the skin.  After masturbation, it can become a darker purplish color.  It can itch after masturbation, although I presume this is from irritation.  

Any ideas what this could be?  My last girlfriend and I were having unprotected sex and she had cheated on me so there is a possibility I could have contracted something from her, although I hope this is only the remnants of a pimple or pustule or something benign.

Thanks.

[JessyJames2010]

continue to work with you doctor on wht the bumps could be.

[xoddus245]

Went to the doctor have this checked out.  It was a clogged, infected pore.  Had a full range of STI tests run, just to be sure, and everything came back negative.

[JessyJames2010]

Hi

Sorry about infedelity in your relationship.  For a better side of things, ---fortunately someone who cheats does not mean they are infected with an STD, they only put themselves at risk for it.  

You should test for ulcerative STDs if you want to rule out the worse thing this could be.  
They are syphilis, gential warts, and herpes.   Only a test and physican can help you idenifying what those bumps are.