What causes discoloration patches on my cheeks? they are lighter than my normal skin tone and quite distinguishable.

Pityriasis alba: Pityriasis alba is characterized by round or oval finely scaling patches of hypopigmentation, usually on the cheeks. The lesions are sharply demarcated and occasionally pruritic and are found primarily in children and adolescents the condition may recur, but spontaneous clearing is the usual prognosis. Treatment includes lubricating creams and topical corticosteroids.

You don't specify...: ...Your age. Pityriasis alba (literally "white spots") is common in children but unusual in adults. Tinea versicolor, a superficial yeast colonization, can occur on the face, and can create light spots. Vitiligo can occur on the face, but the patches are white, not merely lighter than surrounding skin. You really should have a dermatologist take a direct look and give you a precise diagnosis.