I think your condition may involve a gland problem ,likely a minor salivary gland. when partially blocked or inflamed,they can secrete a syrup like fluid that can cause the lips or mucosa to crust and change color. You should see a oral pathologist and see if you have cheilitis glandularis. Someone posted a few yrs back that they saw a specialist at Johns Hopkins and took a drug originally made for leprosy that eliminated their cheilitis.You may need a gland biopsy. A vermillionectomy can be done in severe cases.