What does it mean to feel like you have a film inside your mouth? corners of mouth are dry and lines (wrinkles) going down each side of my mouth have appeared (seems like overnight)..

This : This sounds like a condition called cheilosis. This is a condition that causes scaling and fissures at the corners of the mouth and is caused by riboflavin deficiency. Riboflavin is also known as vitamin b2. Your doctor can do a simple blood test to see if this is the cause. In the meantime you can try increasing riboflavin in your diet. Some foods high in riboflavin are: liver almonds soybeans cheese fish wheat bran sesame seeds sun dried tomatoes remember a trip to your doctor will be necessary to correctly diagnose your problem.

Xerostomia?: Overnight changes may be caused by medications that induce dry mouth by diminishing salivary gland secretion also known as xerostomia which can lead to increased bacteria in the mouth and a plaque. This can also contribute to dry skin. However this is just a shot in the dark and there are many other potential causes.