STD? Pictures included

[Yeezus]

So I have been having unprotected sex a lot recently, and my penis has started to get red pimple like dots on it's head and shaft.

http://imgur.com/a/QgKwP

It itched one day but now it doesn't. It started off as 3 little red dots and has started spreading.

Can anyone tell me what it is? It's really concerning me, as I have never had this effect after sex before.

Thanks

[kapster1978]

What has been your risk?

I have not checked the picture, but red dots could mean a lot:
Herpes
Yeast infection
Chlamydia

If the become open sores it could be:
Herpes, but then they will dry in quite quickly
Syphilis

based on your symptoms I would have STD test. For most STD's you can do that in 2 weeks post exposure. For HIV, Syphilis 6 weeks (in my country to be conclusive 12 weeks) and for Hep-B 12 weeks.