What Causes Dark Brown Patches On Cheeks?

does copper t make you fat and does it bring about melasma. i am fifty years of age. weigh 64 kgs. stand 5.5 ft tall. nearing menopause. inserted a copper t two years ago. have begun to develop small dark brown patches on both my cheeks. dr. says it is melasma. also have begun to put on weght and have develped a tummy inspite of exercising