I suggest that you go to see your primary care doctor
or your dermatologist
about this issue. Any stubborn or persistent skin issue should be investigated by a doctor, because this is the easiest way to quickly figure out what is going on and get you on track with an appropriate and effective treatment.
One possibility is that you simple have what is known as macerated skin, which is a term for skin that has become overly soft and moisturized (think of what your skin looks like after you get out of the tub after a long bath). Believe it or not, applying band-aid continually to the skin can trap enough moisture in the skin to create this problem. For example, if you have been applying a band-aid over the corn, this might be causing the soft spot and simply removing the band-aid and letting the skin dry might solve the issue.
Fungal infection of the skin, called athlete's foot, is also a possibility. Usually fungal infections causes redness and itching of the skin, and there may also be an odor. If you do turn out to have a fungal infection, your doctor will be able to recommend an antifungal cream to clear things up.