How Long After Facial Botox Can I Get Dermal Fillers?

Thank you for the question.
You can combine injectables on the same day to personalize your treatment.  I perform this as part of a "Liquid Lift".  Neuromodulators like Botox can relax frown lines and hyaluronic acid injectables can lift the crease left behind.  Studies have shown that the results of hyaluronic acid injectables last longer when used in tandem with Botox.
As always, an in-person consultation with a board certified dermatologist with cosmetic training is the best way to assess your needs and provide medical advice. 

Botox and fillers can be used at the same time.  There are times that we will do things in a certain sequence.  For example, Botox may be our first line treatment, then injectables to get the desired result.  In our office, we often do peels and then Botox and injectables.  If the patient gets the Botox or injectable first, we wait three weeks.Remember that patients should be off of things that can cause the blood to be, "thin", and cause bleeding or brusing. (i.e. aspirin, ibuprofen, ginko, etc;).It is important to communicate with your experienced injector and be on the "same page" as to the desired result.  Please have reasonable expectations.   Jeffrey J. Roth, M.D., F.A.C.S.Board Certified Plastic SurgeonLas Vegas Plastic Surgery

Botox and fillers can be administered on the same visit and is commonly done.  An experienced provider can look at your facial needs and adjust dosages and placement of both types of products.  As you may know, effects of fillers can be seen right away while full effects of Botox will develop over 3 days to 2 weeks. 

Wrinkle fillers and Botox or Dysport, used together, make an excellent same-time combination treatment. While Botox and Dysport weaken harsh muscles of expression, fillers plump out wrinkles, and each magnifies the benefits of the other.

It's perfectly safe to inject Botox and fillers at the same time even in the same area.  However, if you want to wait to fully evaluate the effects of your Botox treatment first, then you should wait 3 weeks.  The full effects of Botox can take 3 weeks to appear.