I had used drysol and it made my armpits really dark/black. how do i cure it and get it back to my fair color?

I started using drysol and it worked effectively. Although I did experience severe itching after a few weeks, I used it as soon as it occasinonally went away. I know, big mistake. I should have discarded it at the first signs. But now I had had enough and am left with dark, sorta black ish, armpits. I am naturally fair and this is something VERY unappealing and unnatural. Please recommend any natural or medicinal remedies for getting it back to normal?