Thin lips may require volume in both the upper and lower lip. However, some lips may also have adequate volume, but not a very good shape. Cupid’s bow at the vermilion border may not be well shaped or may not have well defined philtrum ridges and it may result in a flattened upper lip. Asymmetries may also be present between the right and left midface or may be lower lip is too much thicker than the upper lip or vice versa.