That's very interesting what you had to say about your lips not peeling when you were in Mexico, I've had a similar experience. As for an explanation of why this may be, here's a link to my original post where I talked about a trip to Mexico:
By the way, the treatment that I was talking about in the link above didn't work, I don't think that the Dead Sea Salt product I was using had the same effect as the water in Mexico. One more thing, how did you like Ixtapa? I enjoyed my trip to Mexico and would like to go back, do you think Ixtapa is worth checking out?