Well his finger nail could have scratched you down there. My boyfriend has done that to me before. And it will make it burn and be bothersome. Sometimes even itchy. And IF he did scratch you it could make you bleed a bit. Put some vaseline on it for a few days. NOT inside though. IF it doesn't go away after a few more days of that I'd see a dr to be sure.
Sometimes if a guy fingers you too much, it can irritate your skin. Remember, you have very thin and sensitive skin down there. If you were not enjoying it, then you were probably dry meaning he was just rubbing dry skin so that would obviously bother it. Give it about 2 or 3 days and it should go away. If not, then I would go to the doctor to get it checked!