Single red bump/dot on penis head can it be STD?

[helpplease455]

So I noticed this red bump on the head of my penis. It basically has no feeling on its own. On some occasions there is some dull pain that occurs for a few seconds but it does not just happen at the spot of this, it will happen on the other side too and I have experienced this feeling before but maybe now it feels more frequent... The spot is raised a tiny bit, when I would rub it it would feel irritated and maybe ticklish but that is basically the extent to it. My last sexual encounter was 45 days ago, I'm having trouble cross referencing what this is to any of the cosmetic STD pictures online but I've never had this before so I feel it has to be sexually related.. Below are pictures that are midly NSFW, they show the head with the bump.

http://imgur.com/HCl4YyO

http://imgur.com/F76yuIU

Since my last sexual encounter I tested negative for chlamydia and gonorrhea at 12 days past, negative for HIV and syphilis at 28 days past and pray those are all accurate..... I do not have any problems urinating. Does anyone have any idea what is...I am fearing sexually related because I have never had anything like this show up before.

thank you for looking

[gracefromHHP]

have you had this looked at? It's either just a bump or could be a wart from your description of it (not looking at photos of your genitals).

Have you had your gardasil shots?