Dull skin usually has one or more red or brown patches sometimes accompanied by open pores & greasy or flaky spots. It is often the result of improper care & sometimes due to stress, poor diet, internal illnesses or hormonal imbalances. Products containing glycolic acid, retinol & vitamin C work well for skin brightening & for enhancing the glow of your complexion. For more persistent problems it is recommended to have a detailed skin evaluation with your dermatologist.