hello, the most common causes of recurrence of leukoplakia
is repeated trauma in the region, either by tobacco,brushes or from sharp edges of tooth/traumatic occlusion..
its good your lesion is curing now.. since 9 months have been passed and some white lesion still exists. i will advise you to consult an oral medicine specialist and get your occlusion checked and remove if any irregularties are noted there.. even if it doesnt regress then you can also go for excisional biopsy
of the lesion which will remove the lesion completely..
you should stop all adverse habits.. antioxidents will help you in treating the lesion.. get nutrional and healthy diet full of raw fruits and veggies rich in antioxidents..