I have used Dermalogica's Gentle Cream Exfoliant. I usually go on Ebay and look for the sample packs, and can get several at a decent price. You just apply the cream like a mask, leave it on for 10-15 minutes, and then wash off with warm water. My skin feels so smooth after. I believe Ulta also sells Dermalogica's products.

ETA: Maybe dial back the Differin to every other day and let your skin repair? Also, are you using a good moisturizer?