How can I treat bald spots in dogs?

Q. How can I treat bald spots in dogs?
A.
I changed my dog's diet. I spent a lot of money to buy many types of antibiotics, allergic pills, Three smart vet MD didn't help me. They continue (8 month) to prescribe for my dog another type of medicine. May be they wanted to make money or just not smart enough to treat my dog. I gave up. I decided to learn about the dogs by myself. Thanks to Google search. Finally I've found online 'magical pills'  for $15. Wow! It works.

See Pic before and after 1.5 month. I believe after another month my dog will be re-born.






Updated after 3 months: healthy dog without any skin and hair problems