The major advantage to Hyaluronic acid dermal fillers is that they are reversible. They can be dissolved with Hyaluronidase, which is an enzyme that breaks down Hyaluronic acid to remove unwanted filler. This is a solution that is injected in the areas of unwanted filler, the filler starts to break down immediately with full effects seen within 24 hours. Dissolving filler can also be corrective, removing filler that was part of a  treatment preformed elsewhere, and re-injecting filler to create the desired look.