Where I practice in Orange County Juvederm and Restylane filler injections are very popular for lip augmentation, lip shaping and for other uses. in my practice I use these hyaluronic acid fillers frequently to correct lip and other facial asymmetries. Unless it is do to scarring or a growth, such as a hemangioma or cyst, most lip asymmetries are due to unequal motor innervation to the lip, which causes the lip to pull up more on 1 side, giving the impression that one side is fuller or larger than the other side. I would recommend you seek out a board certified specialist, such as a dermatologist, who spends much of their time injecting fillers, especially lips. Lip shaping and injection is an art and as we have all seen, especially in LA and Orange County Juvederm and any filler, in inexperienced or unartistic hands, can look bad, overdone or obvious sometimes.