We can not diagnose for you on line: that requires magnified examination, and lab testing.
As to the possibilities: atheletes foot is very possible.
Eczema is possible as well.
A scrapping for the lab is needed to confirm this.
There are less common possibilities with this appearance, such as autoimmune disease, trauma, and circulation problems.
See your doctor right away, but it is likely you need a prescription anti fungal.
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