It is important to know that all pores in the skin are open. They can’t be closed. However, you can improve their appearance and make them less visible by making changes to your diet and skincare routine. Due to their appearance, large pores or visible pores are referred to as “open pores.” Open Pores on the face occur when a person has enlarged oil glands under the surface of his or her skin near hair follicles or sweat glands.