Actually you can get an std even if you've never had sex. And you can get them from oral sex and as you say slight contact with the genitals.
That doesn't mean this bump you have is anything though. Could be a shaving bump like you first thought or it could be something called a papule, which is a harmless bump that a lot of guys have. Or it could be something more.
As far as the wart being transferred from your hand, no. Warts that appear on the hands, feet, etc. Are a different strain of virus than the ones that appear on the genital, so that's outta the question.
Just to be sure, go to the doc, get it checked out. It is possible that you got something from the girl you did oral with. Just get it checked out, let your current girlfriend know and be prepared to answer lots of questions because if you do have an std, she'll think you lied about being a virgin. Good luck! Let me know if you have any other questions.