Cheilitis is associated with many conditions from Vitamin B12 deficiency, iron deficiency anemia, be a symptom of allergies.can also be caused by taking the (retinoid) drug
Isotretinoin (brand name Roaccutane).
Applying protective paraffin-based ointment (such as Vaseline) or lip balms to the lips is normally very effective. Also take Vitamin B supplements.
Some causes of the symptoms you mention, could be lip biting, lip licking, Vit.