As long as the root ball didn't freeze solid, it might have a chance in coming back. You should have taken it to the next step after cutting it back....protecting it from the cold. Begin watering it and prevent it from freezing. If new growth emerges, you may want to divide your fern into 2, or repot into a larger container.

Boston Ferns can live for many years.

I got a good deal on some ferns in Lowe's - they were running out of space and put a load of them on sale. They were so beautiful over the summer and had a cold tolerance of only 40 degrees or so. I decided to put them in my garage and in my loft of my other detached garage. They are very green and are surviving the temps there and I am sure there were nights that went below 40 - but they were inside and the cold did not last long - Good luck - Carrie