Recently i have been developing these whitish patches on my face....mostly on my cheeks and above my lips. i haven't changed any of the products i use. what could this be and how should it be treated?

May be a fungus/yeas: White skin discoloration, particularly one that gets worse with exposure to sun, may be a yeast/fungus infection of the skin. You should be evaluated by your doctor or dermatologist, and they can prescribe an appropriate medication, most likely topical cream or lotion. Meanwhile, you should try to avoid direct sun exposure by wearing sunblock and hats.