Hello. Thanks for writing to us at healthcaremagic I would keep a possibility of Pityriasis Versicolor, which presents as scaly brown colored patches on the shoulder, neck and trunk. The patches may leave behind post-inflammatory hypopigmentation, which is the result of azaleic acid, a skin lightening agent, synthesized by yeast. The etiology of P. versicolor is a yeast, Malassezia Furfur which is a part of the normal commensal flora of skin. If I was the treating doctor I would have asked you to us a topical antifungal cream e.g Ketoconazole 2% cream, twice daily over the patches. A single dose of an oral antifungal e.g Fluconazole 400 mg is also curative. These are prescription drugs, therefore I would suggest that you visit a dermatologist in your region for confirmatory diagnosis as well as a prescription of these. Hypopigmentation may persist for a few more days after the infection is treated. Sun exposure for 10 - 15 minutes daily, may prove beneficial in bringing the color back. Regards