Hi Oral leukoplakia is precancerous . But as you have stopped the habit and your biopsy reports are free of malignancy, you need not to worry. Generally stopping the habit resolves the disease. But if the patches persist they can be removed surgically. Your dentist will be able to guide you with a proper treatment protocol as they have your complete history and has seen the case clinically. Hope that helps. Dr.Nisha.Harwani