Why do our lips get chapped?

We’ve all suffered with chapped lips in the winter: itchy, flaking, sometimes even bleeding. Yikes! One of our listeners wanted to know how this happens, so we asked dermatologist Roxana Daneshjou to explain.   Got a Moment of Um question for us? Send it to us at BrainsOn.org/contact, and we’ll ask around for the answer. See omnystudio.com/listener for privacy information.