One corner of my dad’s lower lip has become a little lighter over the past year.There is no such thing as swelling. no pain or itching. But we have noticed that when he is more anxious, the place becomes a little redder and when the anxiety subsides, it becomes normal in a few days.It also happens in winter He smokes.Daily 3-4 bidi he usually consumes.No other symptoms have been reported so far..he has mild sugar problem.Is it really a matter of concern. or normal