I'm sorry I'm not optimistic. Mush can't be revived anymore than Frosty the Snowman who was reduced to a carrot and a couple lumps of coal. But you can easily get new ones at the garden center.

If its the outdoor variety don't give up on it.Cut the dead leaves off - it should regrow. If its one of the tender varieties its most likely had it...

Assuming you mean Calla lily, and its the hardy one with white flowers Zantedeschia 'Crowborough', it will put out new growth. I'm assuming it is the hardy one because otherwise, it would have died during February when we got the so called beast from the east, if not earlier.... If its actually true Arum, they're hardy and will also grow back. This assumes the plant is in the ground rather than a pot.

I have some that I'm tempted to give up on every year because this happens and they really don't look as if they will survive, but they always come up trumps in the end.