Would the bag be better than this you think?
I thnk that applestar intended that as a temporary measure, re-potting it was the correct thing to do. Now you must keep it secure from your pet and provide it with a good environment. You essentially have a large cutting so deal with it as such. Actually, the bag (clear plastic) idea can be useful even now that it is potted. A humid environment may help it recover. With little rootmass the tree will not use water at the same rate it did before, so watch the frequency of watering. If you bag it (pot and all) water it well first and then it will not need watered as long as the soil is damp and the air (inside the bag) is humid. While bagged, be careful not to place it in strong sunlight as it may get too hot inside.
You have not told us much about your tree. What species is it? How are you managing it, what type of lighting and your watering practices, etc. The more information we have the better chance we stand of helping.