Many people observe things on their penis that appear to be new but in fact have been present all the time -- but seem to become more noticeable because of anxiety, concern about infection, and so on. In that case, perhaps it is nothing abnormal, just some minor variation in the skin. However, if you are certain the bumps are new, then perhaps genital warts or molluscum contagiosum (a minor viral infection). However, the symmetrical occurrence (similar bumps on both sides of the corona) and the arrangement in straight lines both are against warts or MC, or any other STD.
My guess is that this is nothing important, and not an STD (and probably has nothing to do with your casual sexual encounter 6 months ago). But you will need to see a health care provider to get a proper diagnosis. Either your primary care provider or your local health department STD clinic would be good options; either one would be able to tell on quick examination whether the bumps are anythign to be concerned about, but I doubt it.
Good luck--- HHH, MD
Thanks for the reply that helps alot. Only question is that it was 6 1/2 weeks vs 6 months is it still the same answer. Thank you in adavance.