Athlete’s foot is a recurring problem for me, and has been for as long as I’ve worked on my feet full-time. As such, I’m more or less treating it all of the time.
Here’s what works best: at night, sleep with your socks off and point a fan at your bare feet. Make sure you’re hydrating too, because this will tend to dehydrate the rest of your body. The spray powders and stuff and the store are too expensive and not very useful. At least, not nearly as useful as pointing a fan at your feet overnight. If you’re going that route, use coconut oil (H/T Tex), because it’s cheaper per application, works about as well, and doesn’t get wiped off every time you put on or take off your socks.
In my case, the trick with the fan (alone) disappears most outbreaks of athlete’s foot within a few days. Coconut oil, applied twice per day, requires about a week to make decent ground. Store-bought powders and stuff also take about a week. A combination strategy of coconut oil and the fan works very quickly.
I tried the coconut oil thing by itself because I’m sleeping on a loft bed these days and it’s awkward to stick a big box fan up there with an extension cord.