The two situations, and they are not alike
The urgent one. If filler compresses or enters a blood vessel, blood supply to an area of tissue is compromised and hyaluronidase is the treatment. This is uncommon and extremely time-sensitive, measured in hours rather than days. Skin going white, grey, dusky or mottled, pain that climbs rather than settles, or any change to vision is a call-immediately situation, not a wait-and-see one. That's why asking whether reversal agent is physically on the premises is a completely ordinary consultation question.
The elective one. You don't like it, it's lumpy, it migrated, there's too much, or it's sitting in a place that's no longer flattering. Not urgent at all, and the entire difficulty is deciding whether now is the right moment.
The rest of this page is about the second.
