@Markerrag -- I don't know. If I were a tobacco chewer, I would be worried about discolored spots on my tongue and would likely at least go and get a checkup at my local doctor. I would probably do everything I could to detect that stuff early on because it can be disfiguring, deadly and all kinds of things.
Congratulations on quitting. I understand that can be tough, but could add some years to your life.