Is his sole is white and flaky, it sounds like it's just exfoliating sole. It's completely normal, like shedding skin. If it's been muddy where you're at, that's usually when the sole exfoliates more due to the moisture. It's excess sole shedding off.
As for the cut, it could be very insignificant. I'd get his tetanus shot and keep the wound clean. He probably poked it while grazing.
There on the tips of fair fresh flowers feedeth he; How joyous his neigh,
there in the midst of sacred pollen hidden, all hidden he; how joyous his neigh