Got any photos? I'd start by pruning back the obviously dead parts to live wood, and giving the whole plant a good shower if you haven't had any decent rain yet, to rinse off any remaining chemicals.
Next year better rig a tarp over the plant, or move it if you can. Also, try putting the ice melt in old pantyhose and tying the ends, it should help contain the crystals. That won't prevent contamination of the runoff, but might help some.