Yesterday, I noticed that on my left foot , in between my 3rd, 4th and 5th toes, it started to hurt, and the more I walked, the more it hurt. I looked at it last night, and noticed it was really red. If I'm not wearing socks or shoes it doesn't really hurt that much until I walk, then it's just a little bit of pain. The redness has gone down a bit, but it still hurts. Not itchy or anything, just hurts, almost like a burn. Nothing like this has every happened. I walk a lot, and know my feet sweat, and maybe it's related.. What could this be, and how can I treat it ?