my mother had foot problems for years. She had lost a lot of feeling (diabetic for over 30 years) in her feet. I sure you already practice good foot care. I am also diabetic. If your wound will not heal don't wait too long see your doctor. I had a cut that took weeks to heal. Infection comes very easy!
Hi,
for a nonhealing wound you should see your doctor for expert care and advice, particularly that your home remedies haven't worked.
I believe that cortisone would be no help if there is an infection (could make it worse)...
Very good control of your blood sugar would also be required, i assume you have diabetes.
If you cna't afford to see a Dr. at least go talk to a pharmacist to see what would be appropriate care and they could tell you if you should go to a dr. or not.