Hello,
From the symptoms it can be Fordyce spots( these are a natural occurrence), folliculitis or clogged pores. Maintain good genital hygiene by cleaning with soap and water, don’t try to squeeze the pimple. Applying ice would reduce redness, pain or swelling. Also Neosporin ointment and calamine lotion and avoid messing with it. See a dermatologist if problem persists for more than 1-2 weeks.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
I also forgot to add that the bumps do not cause me any pain or irritation, and it was the beginning of September when i had sex with this girl. That was the only time i had sex.
I forgot to add that the bigger bumps are on the underside of my penis, and stop before the tip of my foreskin.