Athlete’s foot does not produce pus and it should not have pus. Pus is from blisters. Gangrene’s clostridia bacteria produces blisters with foul pus inside.
If the pus is in an open wound or in a blister or boil, and the pus does not smell foul, and there is no green colored skin around, then the pus is not gangrene pus.
No matter what, wash vigorously with hydrogen peroxide, clean the open sore nad wash out the pus.