What is the best way that is cost efficient to get rid of scars and skin discoloration? (Photos)

I had a rash in both armpits that began 2 months ago. I kept itching it and made it worse causing it to get swollen, burn and very itchy and red. I used it hydrocortisone cream and antifungal cream to help with the itching and burning and it did. But now I'm left with a bad scar and really dark armpits. Sometimes its still itchy but no redness or bumps. What can I do to get rid of the scarring and darkness.