If a CURB took a chunk out of your seatstay you are probably toast, I would get a new frame. That kind of impact would also likely result in many fracture cracks all over the area thare are not visible to the eye. Yes a picture would be helpful. I doubt if a curb took a chunk out of the frame, it would be small, but small is all relative. Plus a failure of a seatstay while riding could be devistating.