Trying to identify 2 bumps on head of penis… my doc and dermatologist are stumped. Any ideas?

NSWF I have had two bumps on the head of my penis for three months, and my PCP and dermatologist don’t know what they are. I’m hoping someone here might be able to help. The bumps, which are located a few centimeters apart on my corona, look more like mini mosquito bites than growths of any sort. They are somewhat shiny. They usually look reddish, but other times, they are closer to my natural skin tone. They haven’t increased in size. They don’t hurt or itch. The skin between the two bumps appears a bit darker than usual. Two weeks of a prescribed dermatitis cream didn’t help, so I had them treated last week with liquid nitrogen. The resulting blister on top of one of them has fallen off, but the bump is still there and looks pretty much the same as it did before. I’m waiting for the blister on the other one to fall off, but I’m guessing I’ll have to go back for another cryotherapy treatment. In the meantime, I wanted to see if anyone has any insight that could help give me some peace of mind. I’m a 27 year-old white male, 5’6”, and 130 lbs. with no relevant medical conditions. While an STI would not be impossible, neither my PCP nor my dermatologist mentioned it. Thanks in advance for any help!!

NSFW pics: 1: http://imgur.com/a/04KKs 2: http://imgur.com/a/0EL4R