Hyalase is an enzyme that breaks down hyaluronic acid (the substance which most fillers are made from.) It can be found naturally in the body. When a Hyaluronic acid filler (such as Juvederm or Restylane) has been used and given undesirable results such as asymmetry, lumpiness or overfilling then Hyalase can be injected to dissolve it. However, Hyalase should only be used when the benefits outweigh the risks as it can lead to the loss of some of your own natural Hyaluronic acid. This procedure also requires a patch test to ensure you are not allergic.