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Hayou have not mentioned since when is it ther or it's recent or developed after any beauty treatment .because if its since long then it wil take time to fade .
Nany skin lightening product can hardly cure a hyperpigmemted patch in few days unless it is a chemical peel .But dont worry as there are many methods to mask it or lighten it temporarily .
You should visit a dermatologist
who ll determine your skin type and problem n treat accordingly .till then drink plenty of water , have a balanced diet, ur may take a multivitamin
.try natural alovera gel applicatipn.