What kind of shoes and socks are you wearing? Does is itch? Does it smell funky? Is it kind of crusty and yukky?
It sounds more like fungal or yeast infection type thing to me.
From what you've said, I would try getting some air to your feet, and maybe an athletes foot creme or powder. If you're wearing hose and closed toe shoes/boots, etc. your feet are not getting enough air, the mushrooms will be sprouting shortly, lol.
Cotton socks and some shoes that breath, with the weather getting warmer, ditch the socks altogether and wear sandals, and not those cheap plastic things.
When my boys were in highschool and in sports, lots of sweating and shoes on from 6:30am to 7 pm and later on weekends for games, their toes looked the same way. I think your tootsies just need a breath of fresh air! Hubby had the same problem when he was trainwrecking and would spend 24 hours or more in one pair of boots, even if he changed his socks. Plus when I was a kid and we spent a lot of time in rubber irrigation boots moving pipe on the farm, we had that. If getting some air to them, and some gold bond powder or the like does not help, I'd go see the Dr.