Bleaching face went wrong. I'm 3 shades darker than my actual skin tone! Please help!

I used a bleach on my face and neck (only after testing it on hands first), that claimed to be herbal and was recommended for sensitive skin. But idk how or why but I am 3 shades darker than my actual color now!! Please help me! I am completely baffled by this. Cancelled the event I was preparing for... What shall I do now? How many days will it take to get my color back?

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