What should I use as an exfoliator for peeling skin from using differin (adapalene) 0.1% gel? I've been using for 5 weeks; this is the 1st time I've had peeling.

No need. Most retinoid creams (including differin) cause peeling sometimes, especially during cold weather. Often, all you have to do is apply a little less each night. You can also use a light moisturizer if you wish (one that says "non-comedogenic" on the label). If the peeling persists, try skipping a day of treatment. But exfoliation just causes more peeling in most cases.