What Could Be Causing Persistent Dryness, Inflammation, And A Burning Sensation Around My Lips?

Hi, I have dryness around my lips that keeps persisting every now and then. The area around my lips (the upper area and lower area) gets very dry and white dry coating forms there. Also my lips get inflamed along with a burning sensation around the lips and the area around lips gets very dry that it pains to stretch it. What should I apply in such circumstances? and what skin issue is this? Dermatologist are unable to understand this.