Painless flat red bumps on penis

I was sexually active with a female unprotectedly. Maybe  a month later i discovered small, painless, itchless, flat, red bumps around the shaft of  my penis and a few on the head of the penis. I was tested for chlamydia and gonorrhea and both tests came back negative. I looked up the symptoms of herpes and this did not pertain or favor herpes in any kind of way. Nor did these bumps favor HPV and not even molluscum contagiosum. Anyway, in about 2 days the bumps disappeared and i haven't seen them since. Is there any ideas what those bumps could've been? Side note; I am uncircumsized. Please, give me some ideas on what this could've been so i can do more research. I cannot go to the doctor to find out because the bumps are gone, vanished.

[Vance2335]

I would not worry about it, bumps can be so many different things and if they went away that quick then it is not STD related. It could have just been in ingrown hair, pimple, irritation.