First, get rid of the tobacco for good. There are all kinds of chemicals added to tobacco which can and will irritate your mouth.

To me it appears as if its just a thinner section of your gums which is making it so you are able to see some of the tooth. Do you know how long this has been there? Is it painful?

If its still there follow up with an experienced ENT. RELAX! Worrying wont change anything, it will only get you upset.

Take a look at the photo gallery and click on each photo. Try to see if you can guess which ones have serious problems and then click on diagnosis and you will be surprised that what sometimes looks the worst isnt that serious.
OCF image gallery

Hope its nothing!