That's why its better to have a steady gf. I know too many bro's who caught crap being reckless. Here's a clue, they won't tell you if they have something. And my face is too pretty too mess up with open sores.
But for you less attractive guys it may not make much of a difference, so do what's right for you.
You can definitely get herpes via oral.....you can get it from kissing someone then if you perform oral on a woman you can give it to her genitally.....fun stuff...