Thanks for your query, I have gone through your query.
The ulcers what you are getting repeatedly are nothing but recurrent
aphthous ulcers, these can come secondary to stress or
nutritional deficiency.
Nothing to be panic, lead a stress free life, take proper nutritious diet.
If i am your treating doctor, i would have suggested you to take topical
anesthetic and analgesics like 2%lignocaine and choline salicylate gel (anabel gel) apply 3-4 times daily before food and
topical steroid like
triamcinolone acetonide 0.1% 4-5times daily after food.
Do saline gargling. If the lesion does not heal in 5-7 days then consult a oral physician and get it examined.
Regarding you tabacco chewing habit, when you know it can cause cancer, you better quit it gradually. Other wise, once the changes occurs in the mucosa its irreversible. So better quit it.
I hope my answer will help you, take care.