Okay, you have several options.
1) Try scrubbing your lips with you toothbrush or make a homemade sugar-honey scrub for exfoliating your lips. This really helps remove dry skin.
2) What type of lip balm have you used? You might be allergic to something in them. A few that have worked for me are Softlips, Blistex Complete Moisture, Burt's Bees (original version), Carmex (in the tin; the ingredients are slightly different from the tube version... best for super dry lips because it contains all this great stuff, look at the ingredients on the website), and Palmer's Cocoa Butter stick (very moisturizing, great bang for your buck, my favorite so far). I actually don't like Vaseline or Chapstick, I've found them to be very overrated (and Chapstick's loaded with alcohols! ick! that's just going to dry your lips out more!).
3) Realize that chapped lips can be caused by allergic reactions. Sometimes I randomly get extremely chapped lips and I think it might be because of allergies. Try taking Benedryl, it might help.
4) If truly nothing works, you'll need to go to the dermatologist. He might be able to run some allergy tests and assess your condition.
Chapped lip experience