What Causes Large Open Pores On Skin When Exposed To Sunlight?

Hi, I have used Tretinoin/Hydroquinone prescribed by a doctor (OBAGI products) for 6 months, it was probably one year ago. After that I ve been using some other products from zo medical/zo essential (Obagi brands) that contain retinol. I have used sun protection, but through work I spend a lot of time outside. Now my skin on my cheeks and for head starts to look like orange peel (with extremely large pores). I read about a lot of other people who got this problem, some say it is collagen damage from the sun, others that it s just the skin being thin and dehydrated. My skin doesn t look dry or red or anything, just dull and with extremely large pores. Is there anything I can do to get it better?