Large pores takes time to treat. The cause could be from longterm cleansing agents that was not correct for your skin.
Something that we have found to work very effective is treating with fruit acids. Unfortunate for you your skin is sensitive so it could burn your skin. However you do mention that your skin is combined too. Oily and dry? We would recommend a proper cleanser such as the Cleanser Soap Free. The glycolic acid is a 10% that can be diluted with water in your hand before application. It can be used for short periods (2min) as a gently exfoliated. Avoiding the areas around the eye and nose.