My penis is being silly

so here the deal i'm 17, and had sex with this girl, used a condom. then a week later had a pimple like thing on my penis for like 1 week and i popped it and a white puss discharge came out like a pimple or blackhead. then i got another one and then it stuck around for 2 weeks and i just popped it and it seems to be gradually disappearing. im concerned, is it just a pimple from sweating and what not, or do i have an std. Now that i have notice these i started looking around for other concerns. i notice a small area on the underside of my shaft is slightly darker. it is not very noticeable but if you knew what you were looking for u would spot it. once i noticed that i started getting real concerned so kept lookin around, then i notice some red spots on the head of my penis, very very small, and hard to notice. they aren't there any more, is this from irritation of me freekin out looking at my penis so long...lol?

I also smoke lots of weed and maybe that is turning me into a hypochondriac! now all im doing is researching about stds and what not!

i would really appreciate any feedback at all!