A couple months back, my wife adjusted the temperature on my kegerator to make it a bit colder. Unfortunately, she ended up with the keg that was in the back and closest to the elements freezing on us. Turned into a big raspberry wheat slushy. I adjusted the thermostat, and it thawed out over a period of a couple days. However, it never tasted the same, and I ended up tossing the last 2 gallons.
Others may have had a different experience, so yours might be okay.