I have had something similar happen some times, only not half as bad, still do, just rarely.
I always assumed it was some capillaries breaking from the curved fingers and stress in the bent spots working with stiff wires building/repairing fences or holding a rope with something bouncing on the other end of it, like an un happy critter.
It could be similar, brought on worse by the cold, but just in case I would have your Dr look at that.
Maybe you need something to keep blood vessels more flexible/stronger?
I don’t worry, but mine is not that wild and at times I feel it like a sting when doing something that will cause that bruising.
I also have that reaction where at times the whole inside of hands and fingers turn very bright red, like they have a light inside and in a few minutes it goes away.
I think it indicates good blood flow.