Lichen Planus is a temporary condition that affects the skin and lining of the mouth in many adults. It has two basic forms: reticular lichen planus and erosive lichen planus. Reticular lichen planus is painless and is often found on the cheeks, gums and tongue. It looks like small white lines in lace-like patterns and causes no symptoms. Usually, it does not require treatment. Erosive lichen planus is more serious. It causes sores to form most commonly on the cheeks, tongue, and gums. Doctors usually prescribe a powerful anti-inflammatory drug to help with the pain caused by this condition. The exact cause of lichen planus is unknown, and while there is no cure for it, the condition is manageable and usually goes away. If you think you might suffer from lichen planus, talk to your dentist.