I don't know if you have tried this but, I also have this lip problem, and as painful and weird as it sounds if you take a toothbrush and 'buff' your lips it helps get the dead skin off and makes chapsticks and such more effective. I have had my lips so chapped before that they were very close to bleeding but this helps you just have to get through the uncomfortable part.
I personally find Blistex much easier to use and better working than the chap stick type stuff - to me, the chap stick stuff always feels like I'm wearing a candle on my mouth. Whereas the blistex tends to soak into the lip tissues and I find it really helps to hold hte moisture in them and heal them.
One thing to definitely check, though, is that severe chapped, dry lips can definitely be a sign of serious dehydration - so definitely make sure you are drinking enough liquids throughout the day - avoid caffeine if you can, because that will only dehydrate you more. And if you're finding that you're breathing through your mouth more than normal, that could also lead to dry, chapped lips - so if you need to use something to decongest your nose, give it a try.
Try Vaseline. I keep a small jar of it in my night stand for when I have dry lips. its great for when you have a cold too and your nose gets dry and chapped from blowing it.
BEEN THERE DONE THAT, BUT THANK YOU
carolina, have you actually used the blistex that comes in a squeeze tube and is menthol smelling and has kind of the consistency of toothpaste? That stuff works.
I know this is hard to believe, but vaseline and chapstick actually degrade your lips, eroding the very outer layer of your lip skin. Petroleum products should never be used on mucous membranes, and that's why it's bad to use vaseline as a sexual lubricant. It degrades mucous membranes.
You know how so many people are addicted to chapstick? It's because they use the chapstick, and then the very outer layer of their lips is degraded, so they need more chapstick. Continues the cycle.
Neosporin and blistex in a tube should do the trick.