Does Anyone Know What That Crunchy Sound is when Having Fillers Done?

Mixing Radiesse shouldn't put air into a syringe.  The temple fossa is very close to the ear, so when I inject this area I warn people they will hear a whoosh or a gritty cruching sound.  As Radiesse is really a thick emulsion of calcium based crystals, you can hear this products when it is injected or molded or if close enough to the temple muscle, being compressed when the muscle contracts.  Ultimately it all absorbs so the 'sound' will dissipate over time.

The sound you probably heard during the injection is most likely air in the syringe. Radiesse is often mixed with numbing medication and this process can sometimes cause a few air bubbles in the syringe.  As the filler is being pushed through the syringe, it can make a crackling sound.  This is nothing to worry about.  Air introduced under the skin will be absorbed and should disappear without any problems after a few days. It often takes Radiesse a few days to smooth out after the initial swelling from the injection resolves.