cureforcurezone thanks for posting that bit about kids licking their lips. Its was very helpfull.
I want to let you know that the area you are describing as the 'affected area', I dont think was caused by licking of lips. The affected area for me anyway, has always been localized to the same area of both upper and lower lips, never increasing or decreasing in size. It I think, is a certain type of skin on the lips, there from birth and completely normal. I think everyone has this area but in some people, like us, it is just naturally bigger and covers more of the lip. It could almost be called semi-mucous membrane. Half mucous membrane and half skin. This area of skin seems to have both of these two skin types properties.