Am I going to get herpes?

[Telbel10]

Dp went down on me a couple of days ago. The next morning he woke up and had a cold sore. I don’t know how they work and if they really do just appear overnight. And if it wasn’t there the night before would it have been contagious? Seriously freaking out and feel very very upset at the prospect of having herpes

Chances are you have been exposed to the virus previously as he is a carrier but yes it's possible. I'd say it's about impossible to be with someone for years and not pick up the virus honestly, so it would be surprising if this was the first exposure. 50% of carriers never get symptoms. It won't be nice if you do get it but it's not the end of the world.