Hello, Look into possible allergic reactions to new products that you may have started using such as a different lip balm, cosmetics, toothpaste, etc. Eliminate any possibilities and see what happens. Salvia content can change. Effects on salvia can be from medication, diet or a disorder. Infections can be carried in salvia and cause irritation to your lips. This is common with strep. Consider having a dental exam or seeing a dermatologist if your symptoms persist. Dental conditions such as recent change in your bite, grinding or an open bite can cause excess salvia with drooling at night. This could be your excess exposure to salvia that irritates your lips. Do you snore or have a recent change in sleeping habits? Keep very well hydrated and check for vitamin imbalance. I hope that my suggestions are helpful. Thank you for your inquiry.