Thanks for the suggestion, MJ.
Evidently I am a moron! Right after I posted this my other foot went numb, too. Then I remember that you're not supposed to massage or rub cold skin that might have frostbite or hypothermia. I went upstairs to soak my feet in the tub, took my socks off, and both feet were funky colors like white and purple. After 10 minutes of soaking, the skin was still a little cold. 2 pairs of socks later, all is well in the world again.
