Hello thanks for consulting at hcm.. The white patch could be leukoplakia since you had the habit of smoking?? Was it long term smoking habit?? Please stop the habit gradually.. you need to take a consult with a oral physician for a check up of your oral mucosa and tongue.. you may also need antioxidants like lycopene etc Because it is on the lateral borders of tongue, are your teeth surfaces sharp?? May it is also contributing, hence get your sharp teeth surfaces trimmed.. Hope it helps,,take care..