In reply to peebles boy:
Although it's not what you want to hear, my advice would honestly be to rest it, and let it heal properly. Frustrating now, but a better idea in the long run to prevent permanent injury.
But I doubt that is an option, so take it easy, and make sure you keep your hands warm as possible. Consider some padded winter cycling gloves, or decent ice climbing gloves to give some protection. Make some wrist warmers from some support bandage, and maybe take some hand warmers and a pair of large mitts to go on top of everything at belays. If your hands are kept warm it will greatly improve the finger!
The grivel horn, or similar rest might be a good idea, but it might not also. It seems like this will concentrate most of your weight onto the little finger. Perhaps go back to old-fashioned leashes for this season?