Hmmm...I don't know about the redness, but in general, heat seems to aggravate my feet rather than cold, but not necessarily going from cold to hot. Magnesium I'm taking: Nutricology magnesium citrate, 170 mg 3x a day.

I've also been taking your advice to do the epsom salts soaks, which as you've pointed out, also contains magnesium. It really does seem to calm them down, but is it the magnesium, the coolness of the water, or both? Hard to say unless I tried it with just plain water, I guess.