When looking for items that will help with dry, chapped lips or even sore skin caused from winter change look for items that contain glycerin. Glycerin is not only inexpensive and widely available it can be found in all types of over the counter products.
Glycerin has a variety of uses which include acting as a humectant. Humectants are substances that facilitates water retention. This process is important in protecting moisture for the skin.
Glycerin is also believed to play a role in cell maturation.
A study was conducted on mice that were genetically modified so that they didn't have the channels through which glycerol is transported. When glycerol was applied topically or given orally to them, their skin problems were alleviated to a great extent
Finally, at least for this article is that glycerin improves and protects dry skin by filling up the intercelluar matrix and also helps in building an even skin structure.
More information can be found here.