I can't promise you anything, but many of my begonias are outside with frost blankets and in some cases with nothing, and have survived temperatures in the twenties. Sometimes they look pretty hopeless--mushy, with all the top growth frozen--but if I don't panic, which I've been known to do, and clean off the mushy stuff like you have done, it's amazing how many of them will come back from the roots even with heavy damage. Of course, some are hardier or tougher than others, but I think you have done well. I just have too many begonias to bring in, and have to do the best I can to protect them outside or in my very small greenhouse, and I usually lose a few, but they are unbelievably tough--or at least many are! Good luck

Thanks! Lesson learned. The thick stems near the base are still green, though the plant looks mighty upset. I'm keeping my fingers crossed. I suppose I'll know in a few weeks whether it will have made it.

I should have said--probably best to keep them a little on the dry side until they show new growth. And of course don't fertilize until then either.

OK. It's in intensive care in my kitchen. Thanks for the pointers.

Miraculously, the plant is coming back  tiny to smallish leaves are poking out from the lower sections of the near-barren stems (only one mature leaf survived!). Thanks again for the good advice.