The only thing I've learned over time after the shot, is to always assume that it was a hit and track it until you can positively rule out the possibility of a hit, if that means following tracks for 200 yards then so be it, but I have learned that if an arrow or bullet is shot at a deer then I will be tracking none-the-less.

Sorry to hear about not finding the buck, the snow didn't help matters either. After it melts I would go back in there and look for the remains.