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I understand your concern. The pictures are a bit hazy. But from the given images, it looks like a fungal infection by the name of pityriasis versicolor. I would also need to see your chest, upper back, and shoulders to be sure. Kindly send clear photos of the same to make a conclusive diagnosis. Meanwhile, you can start using the following medicines.
1. Tab Fluconazole 400 mg start and repeat once after a week.
2. 2 % Ketoconazole lotion apply for 5-7 mins and wash off once a day.