Oily skin is indicated by blackheads – which are caused by oil – covering the whole face: cheeks, forehead, chin, nose and even inside your ears. Pores tend to appear enlarged. Skin is often shiny and oily throughout the day, although not always as it may be suffering from surface dryness.
Combination/dry skin is more dry than oily. A few blackheads can be found, mostly on your nose and chin rather than your forehead and cheeks. Pores are usually on the smaller side.
Combination/oily skin is more oily than dry, with an oily T-zone that is really more V-shaped, extending from the forehead down across the cheeks under your eyes and narrowing towards the chin. Blackheads are typically found in this area, which is often also oily and shiny unless surface dry.