How to correct Uneven Lips, Crooked Lips, Asymmetrical smile by Facial Exercises. If your lips are uneven, it may be due to your facial muscles being underdeveloped or weak. This could be the result of a condition such as Lyme disease, or it could be present from birth. Facial Exercise or physical therapy to increase the strength of the muscles around the lips. You can perform to make your lips appear more balanced. Step 1 Use the index finger and middle finger to touch the corners of the mouth.