Hylenex (hyaluronidase human injection) is an enzyme that dissolves hyaluronic acid (HA) filler, like Juverderm, reversing its effect without damaging the surface of the skin or the dermal structure. There are several filler reversal agents on the market, however, Hylenex is the least likely to cause an allergic/anaphylactic reaction.  Generally, one vial of Hylenex dissolves approximately 1 ml of filler, but there are variations depending on factors such as type of filler, time filler has been in the body, inflammatory granuloma/nodule, & the degree of urgency. Sometimes a few appointments is needed to achieve the desired results.