When in cold temperatures if your fingers become white and painful what do you do?

That isn't such a good idea. Fingers that cold can't feel how hot the water is, and you might end up scalding them instead. Never plunge a numb body part into water unless you know the temperature is safe. You need to test with a body part with normal sensitivity first. The rubbing is also a so-so thing. If you already have developed frostbite, you have ice crystals in your tissues. Rubbing will damage even more tissue, causing a bigger-than-necessary injury and slow down healing. Rubbing is ok though as long as you're sure there's no possibility of freezing.