Every time I take a hot bath, when I get out, my feet hurt. Not sure why. The kind of burn/tingle/itch. Anyone out there have this problem? What can I do to stop the pain?

Oh and all the bottoms of my socks are always black, or like grey no matter how much or how often I clean them. I buy new socks pretty often and even after the first day, my socks all look the same...