I have asked Dr. B, on one of her other sites, Aabout using my Retin A under my eyes and on my neck. She recommended mixing the Retin A and a moisturizer and using once a week. Another Dr. recommended using a moisturizer with Niacinamide. I mixed Olay active hydrating beauty fluid sensitive skin. Hope this is something I shouldn't by using with Retin A because its an AHA or BHA. What is a good moisturizer for mixing?