I have very very dry skin. My esthetician recommended me moisturizers used by much older women but they work wonders for me. At night I use Visual Changes Phytosome Nutrient Creme. It is pretty expensive but lasts a very long time because you only need to use a dab. During the day I use Face Reality's Moisturizing Sunscreen SPF 30.

I started Differin a few months back as well...a lot of the dryness you're experiencing will pass as your skin adjusts. That said, when I started the Differin...I had heard how sensitive and dry it could make your skin, so I made some changes... in the morning I wash with Phytomer Accept Cleanser. It's non- comedogenic and soothing, moisturizing... pricey, but worth it. You only need a little, so the bottle lasts. I also use Phytomer alcohol-free toner. At night, I used my usual cleaners. I switched to 'Oil of Olay complete daily spf15 for sensitive skin' because it had non- comedogenic ingredients.
It worked like a charm... my hands were dry as all #!@$, but my face was fine. Lol.

When I first started benzoyl peroxide, I had the same problem (flaky dry skin). I would recommend CeraVe (night time moisturizer is better than the day time one), Eucerin or Rodan and Fields Soothe Moisturizer.