Skin thins and dries with age, so lines and wrinkles start to appear. Applying primer before you put on your makeup helps minimize the appearance of fine lines and pores by filling them in. This way your skin is a smooth blank canvas for you to apply your makeup. Skin primer does not get rid of fine lines and large pores, but it can help both appear less visible. Silicone is a common ingredient in skin primer that works well for the purpose.