What is the ruling on swallowing saliva after the lips have been touched by wet head hair from ghusl? And does the wetness of the hair invalidate the fast if it touches the lips, is licked, and the saliva is then swallowed?

You must ignore the whispers and not pay attention to them. If the wetness of the lips resulting from touching wet hair does not separate, then swallowing saliva mixed with it does not break the fast. Even if it separates and the fasting person swallows it, it does not break the fast due to its small quantity. Your fast is valid in all cases. The one afflicted with whisperings should adopt the easiest opinions until Allah cures him.