You should tallk to your doctor but for what it's worth feet smell because of bacteria. When you wash you kill millions of them but they soon reproduce and the smell returns.
--- I have read somewhere that the gas nitrous oxide is the body's natural defence against bacteria as it is a powerful bacteriacide. Another point is that the bacteria live deep in your shoes and trainers. You need to clean your footwear as rigourously as you clean your feet to make a difference.