Frostbite is when you can't feel anything. The tingling may mean your toes are cold or that your shoes are too tight. If you have poor circulation in your legs to begin with, you might need to be concerned. Otherwise don't worry too much about it, just increase the insulation around your feet by making sure the fit of shoe is loose (NOT tight), the sock has good insulation and if needed your shoe has some insulation in it as well 200g thinsulate is as much as I've ever needed this side of ten below.