If you have oily skin you will most likely experience a great deal of excess oil production in certain areas of your face e.g. T-zone. You are also very prone to acne breakouts. Your active oil glands produce high levels of sebum and the oil from inside the epidermis that travels to the skin surface through the pores and hair follicles. This will result in visible pores and your skin could appear greasy as the day progresses.