When my EC initially began, it was only on the lower lip. I was "managing" it by constantly rubbing it off so they would appear normal and I was still licking my lips during this. When the problem persisted, I began looking my symptoms up online and found this forum.
I searched for success stories and stumbled upon the famous "leave it alone" method to which I immediately tried. Within a week, my EC spread to the upper lip out of nowhere and my lower lip was in constant pain due to the unbearable dryness. I honestly have no idea if it spreading was a coincidence, or it spread because I left them alone.
It's quite a shame that in our era of advanced technology, not even the most qualified doctors can explain or give at least a single clue about this condition.