Injection of filler material into a vessel can cause blockage of the vessel with loss of blood supply to the nearby skin/structures. Pain and a dusky appearance to the skin occurs relatively quickly (usually within 30 minutes). Since Sculptra is such a watery filler, blockage of vessels is very uncommon. In addition, most injectors place Sculptra deep in the temples, where there are no blood vessels. If you hear a pop during injection, this indicates that the injection is in a safe, deep pocket where blood vessels do not travel. Injection of the temples, however, can cause pain with chewing temporarily. This is not an indication of intravascular injection.