Hello & Welcome to HCM,
I went through your history & your smoking
history indicates a tendency towards precancerous lesion which can be:-
Leukoplakia-a whitish non-scrapable patch with hyperkeratosis
& smoker's palate are also associated with tobacco use
Oral lichen planus- characterised by presence of bilaterally greyish white lines known as wickeham's striae, it can later affect other parts of body.
these are few differential diagnosis of your diseases but you should go for biopsy for further confirmation.
First & foremost you have to stop your habit of smoking.
Maintain your oral hygiene
by brushing your teeth twice a day & using 0.2% chlorhexidine
Also start with multivitamins & antioxidants.
Later on your dentist
may start with some corticosteriods.