Most likely you have a fungal infection. You should see a dermatologist or primary care doctor since it involves more that just your foot. You may need to take oral anti-fungals. There are some topical anti-fungals that may prove effective such as Miconazole. You should see a doctor an accurate diagnosis. If you are diabetic you really need to get this checked out since you are more susceptible to other problems due to poor circulation. Good luck. Susu

