How can I treat dry lips?

Moisturizers. First, using good moisturizers like aquaphor, second, if developed into eczema, using cortisone ointment, like cortisone-10, third, if still not hlping, see a dermatologists.
Chap stick. Winter time causes dry lips. This is due to the lack of humidity in the air. Until the weather improves vasoline or chap stick is the answer.