at night time make sure you have socks on and keep your feet warm, or it might be that your feet are too warm, in which case don't wear socks at night. Also you might have a circulatory problem(i don't know much about that so you will need to research it)
the most likely thing is that you've got atheletes foor. This is a mild foot infection that can easily be treated by a cream from the supermarkert. It is caused by sweaty feet or not drying inbetween your toes after a bath/shower.
In the future make sure you dry your feet and invetween your toes every time you wash. Athelets foot can be treated by putting talcum powder inbetween your toes and on your feet, however the most affective is getting a cream from your local store or pharmicie.
Hope i helped! x
tried all the above...didn't work! gone through Chemo twice....and had hysterectomy!