Whew. What a relief.
I took my hearing aid to the audiologist today, and the situation is not as bad as it might have been. The innards are still working. It's just the casing that was destroyed. So the audiologist took a new impression and will send that to the factory, along with the smooshed hearing aid with its electronical guts, and they'll recreate the thing for me. Not cheap, but a fraction of the cost of a completely new one.
So possibly by this time next week, I'll be able to hear with both ears again. At least, to the extent that a deafish guy with hearing aids can hear.