The thing I would worry about is your defrost sensor might be shot. It's supposed to detect that the line is frozen and go into defrost mode. When mine does that, the fan doesn't spin and the compressor runs, which heats up everything until you're thawed out, then goes back into heat pump mode. Then it flushes the whole system out, cooling it, and start the process over from scratch. It gets real hot in defrost mode. During the freeze, mine would billow steam and I could see water evaporating right off of the compressor. You might want to pop open the blower and see if the coils are frozen in the house. If so, then you might have a problem. If it's just frozen outside, you might be okay. Either way, getting a tech out might be difficult. If the coils are frozen inside, shut the outside down by turning the system off, but keep the fan on to aid in defrosting the inside coils. You might be able to save the compressor if it is just a sensor or the switch shorted out and welded itself into the on position. Edit to clarify: keep the inside fan on, be sure to turn off the breaker before opening up the blower inside.