Hm, I've actually never heard of this.

<edit> I googled it and found some answers

First they're saying to cut back on smoking, drinking tea or coffee, then apply vasaline, ghee, olive oil, or lemon juice to them to moisturize and lighten 'em. It says it'll take about a month to see a difference..

(http://www.indiaparenting.com/faqs/b...ark_lips.shtml)