How high was the ramp, and what did she land on? If she fell less than about 1ft and landed on something soft and isnt limping hopefully she is ok, keep an eye on her just in case as piggies tend to hide their injuries and can occasionally land badly and hurt a leg or their back... but if it was just a small fall within the cage she may be fine. Maybe you could add sides to the ramp, or some carpet for extra grip, or make it less steep for her? If you are worried at all, always see a vet, but if she is behaving and moving normally I would just keep checking on her this evening and again in the morning.