Posted: 18/04/2012 at 22:57
The only thing that you can really do is leave them and see what happens. With a bit of luck you will get fresh shoots in a few weeks' time.
Begonia tubers - they should be started indoors, just under the surface of some compost; now is a good time. Pot on when they have produced shoots, and harden off before planting in their final positions when all danger of frost has passed.