What is the recommended wait time to get a spray tan before and after fillers, such as juvederm volbella or voluma?

There are no restrictions whatsoever! You can get the spray tan anytime after you've had fillers done. You probably want to do the spray tan after the filler because the fial prep required before the filler injection may disrupt the evenness of the tan on your face.

Studies on microneedling have shown that the holes created in the skin take about 4 hours to close. So, following injection of fillers, I recommend my patients not applying anything to their skin for 4 hours and that would include a spray tan. Also, don't like the idea of having spray tan particles on the top of the skin prior to injections that could be pushed under the skin with filler. Maybe you could save money for filler by not doing spray tans? I wish their wasn't such an emphasis on the tanned look. To a dermatologist it just symbolizes unhealthy sun damage. Be safe and choose an expert injector.