That's been my experience, too.

Wash them twice a day with soap and warm water, then dry them very carefully, especially between the toes. The medication I've used tells you to do this before applying it, and I've found if I do it I don't need the medication. It can take a few days.

Take extra care with hand-washing also. The bugs that live on feet are just as happy anywhere moist, including your bum crack and around your eyes.