Hello there, that's good that you do not chew tobacco, but the details and the picture that you have sent, seems concern full condition and that could be the result of smoking, though not often. You must know that this particular medical condition is still reversible if you quit smoking completely, flip to some healthy diet and exercise. Be stress free and have patience.
Next Steps
You should see a Dentist(as soon as possible ) for counselling and some oral medicine that may include vitamins/minerals and oral gel for local application.
Health Tips
its still not too late!