Well. It's hard to explain. On my bottom lip, it used to be only one layer of crust, devided into maybe 3-4 crusts. When I do leave them on and the crusts just sit there, there seems to be growing new ones (maybe not that fast) underneath. On my top lip, the crusts in the middle has not come off for weeks, and it just seems to be getting "stronger and stronger" (thicker), so it's not like a protective layer over raw skin, it sits directly on the skin and keeps on growing. At least that's what it looks like.