For me, the key to all this is sebum. Sebum is the ingredient in the skin which keeps it waterproof and elastic. Something is blocking the sebum reaching the outer layer of our lips.
The affected areas on my lips absorb water and do not stretch at all. They break into sections with little gaps in between where little areas have to take the full brunt of the stretch.
Now, it's been said loads that lips don't have sebaceous glands, but, if they didn't wouldn't that mean that any time someone got chapped lips they would never recover?
If it is a fungus that's blocking it then I hope this works #64643, I still think that hardened sebum (Fordyce's Spots) is plugging my glands though and finding something to unblock them is the key...