I got frostbite once, got back to the car, turned the heater on, and what pain!!! I could barely walk for a week or two, couldn't even lay a sheet over my toes at night. All my toenails fell out. They returned eventually, except for my two big toes. They look like crap. I did go to a doctor a day or two afterwards. He said he could not do anything, they had already thawed out, and oh, by the way, $65 please.
Might get some good advice from folks here, but best advice, is don't let it happen again. Get better boots etc. good luck