See a doctor
The knot in your calf should be examined by a doctor. In the meantime, stop stretching as it's not helping at this point.
Most likely you have a tear in your calf muscle, which would need some time to heal. But there are other possibilities such as blood clots. If the pain is severe, skip the prom and go see a doctor today. While waiting to be seen, rest, keep your leg elevated, and ice it.