Had rough sex 2 nights, in pain so looked n it was a cut. went to the e.r and the lady said it maybe herpes. its only one cut, is this possible?

Cut: Anything is possible but it is probably not likely. To be certain you can go to your doctor and have a blood test drawn to see if you have any antibodies against the herpes virus. If you don't, then you don't have to worry. If you do have antibodies it still doesn't mean that it is herpes. A viral culture of the sore could be done to look for virus.