Whatever you do, don't go back. I agree with Evilsheepempire that you should tell your parents what happened, but ultimately that decision is up to you. What I can tell you as this: you might not think it's a big deal, but if you go back to him and pretend like nothing happened, he is going to assume, in that sick, twisted mind of his, that you were ok with the groping. Once he learns that, he's going to go farther. Personally, I'd say to tell your parents as well as the agency or company he works for, because even if you never go back and never see him again, there's a good chance that he'll try the same thing on the next underage girl that walks into his office, and this time he might not stop at groping.
Absolutely it is a big deal! It might not seem like something hun, but this is the first step. Many times a guy will try something small to see what he can get away with. If you go back, then he will think that it's ok, and he will try and go even farther. You're putting yourself in a situation where something bad can happen. And girls do get raped all the time. This is definitely not something you should take lightly
Oh for Christ sakes, girl! You should have belted him with a swift backhand and kicked him in the nards kung-fu style right before you called the cops. This sicko is a pervert and if he isn't forced to stop his illegal behavior NOW he will prey on other girls -- guaranteed -- and you could have (and should have) saved the next girl. Sure he may be nice and likable, but that's how they *have* to be to prey on innocent victims. Don't let that stop you from doing what's right. All A-holes like this should be locked up together and castrated (they have a special prison on an island near Tacoma, Washington for guys like this - except the castration part. Even when they've served their sentence they STILL keep them locked up! That's the way to treat these troglodytes).
Honey please do not take that ! He does not need to be messing around with a 14 year old. I have a 13 year old daughter and that makes me furious ! I'd knock his lights out if he did that to my daughter. Report him ! He is an authority figure and it is against the rules to treat you like that ! One thing will lead to another if you don't stop it now. Tell your parents.