I did the same thing, with the same result about 8 weeks ago.This is the second time in my bonsai life! I thought that I was ok because the buds were just swelling with a little green showing?! I'm very sad! I would like to have a larch in my collection some day. The trunk bark is still green but all other growth has stopped! In my gut I don't think it will make it!
I think you have to catch this one the end of Jan in my time zone because we have mild winters and early spring!?