Melasma: I've ethnic skin and due to chronic acne I had post inflammatory hyper pigmentation as well. I got microderm done on my face 4 times at 1-2 weeks interval, without realizing that my skin was too sensitive. I used retin A as well. It left me with dark patches on both sides of my cheeks. A dermatologist said it was melasma. after that I tried many things: lot of sunscreen, azeleic acid, lemon turmeric. but nothing seemed to work. infact I damaged my skin more by being aggressive on it. I decided to give my skin some time. I stopped using too many things on it. totally avoided the sun. and finally when it wasn't very sensitive I started using papaya for exfoliation. i scoop out one table spoon from the ripened papaya and mash it in my hands and slather on my face. if i want deep exfoliation i leave it for 20 mins (else 5 mins) and then rub my face with palms in circular motion. i can see dead skin cells from face in my palms.afterwards i apply fresh aloe juice and then rosehip oil and I'm very happy with the results. the hyperpigmentation is not fully cured but it has faded quite a lot. i still avoid sun. I'm not sure if it was melasma or only post inflammatory hyper pigmentation. whatever it was papaya has lightened it through gentle exfoliation and i'm hoping for great results in future ( I have used it only for 2 weeks). Hope it may also help someone. It doesn't treat hyper pigmentation but just exfoliates effectively. so other lightening agents can still be used along with it. Good Luck.