Thanks for posting your query at DoctorSpring.com. I can understand your concern.
It seems to be an eczema that you have on your foot.
Eczema means inflammation of the skin and is usually allergic in nature. Your body has a tendency to develop the eczema, there needn't be an allergy to an external source.
The treatment for it would be application of an emollient cream like vaseline petroleum jelly and cortisone cream twice a day for two weeks.
This will help resolve it slowly.
Please let me know if you have any queries.