Sexually Transmitted Diseases

[DaKixx]

I wanted to ask , i had sexual intercourse with my girlfriend , and the last sexual intercourse it started to hurt.It was unprotected seeing that i dont ejaculate in her and she's taking birth control pills. Well , it was 4th that day and i wanted to check what was wrong ... Anyway , i found a small lump on it , around i dont know... 1cm . So , i wanted to check out what it was... Anyway when im not touching it it doesent hurt or anything , but when i touch it it is painful like touching a bruise , it has a little yellowish center , not like a pimple or anything , just yelowish middle. So , i tried to test something , so i put a drop of hydrogen-peroxide ( solution for disinfection in case i misspelled the medicine) and it reacted like when you put it on a bruise , it starts to foam a little . Now , im waiting a few days to possibly let it heal , but if i see any changes im going to the clinic . But what i wanted to ask , is there anything similar to this like an STD or something similar , cuz if it is , i want to let's say go earlier to a urologist to check it out fully.

Thank you in advance for your answer