I am a male. Last week I had my first sexual encounter with a middle age female sex worker of Asian decent. Right before the encounter I had trimmed my pubic hair. I had received unprotected oral and protected vaginal sex. 2 or 3 day after the encounter I noticed a small bump on my penis. I scratched it. It came off. The skin started to heal and then there was an off white scab formation from where I scratched it off. The scab later turned dark brown/black and was healed in 1 week. The small bump was 0.3cm in diameter. What was this?