does biotin cause chapped lips
Actually, in my experience, a lack of biotin can cause chapped lips and it seems I'm not alone in that impression. See http://lynncapehartwellnessproject2011.wordpress.com/2013/03/31/blog-29-chapped-lip-skin/ I'll try to find info on the actual biochemical mechanism to shed more light on the issue, and come back and write more if I'm successful in that search.
Yes, biotin can cause chapped lips. The reason for this is because it dries the skin out to a certain extent and can cause chapped lips and skin.