How soon after Botox and dermal filler can I have ThermiTight on the lower face and neck done?

You
don't have to wait for your ThermiTight treatment unless your Botox
and fillers were placed in the exact area you want to treat with
ThermiTight. The only reason to wait is to avoid the risk of
increased swelling and bruising. In that case, you should wait one
week. However, usually fillers and Botox are placed in different
locations, so we often inject them after ThermiTight on the same day
for a beautiful combination treatment. Please find a board-certified
dermatologist to help you devise a long-term treatment plan to keep
your skin looking youthful and fresh. 

As ThermiTight is commonly done on the lower cheeks and neck, and not in the cheekbones, smile folds or marionette lines where fillers are injected, patients in my NYC practice often have both done within two weeks. If there happens to have been some filler in the cheeks where the ThermiTight is performed, there is a theoretical question if the longevity of the filller's effectiveness is affected by the heat produced by ThermiTight, but this has not been proven.

Good questions - you can have ThermiTight done any time with Botox.  The big question is where are the fillers placed? I would wait at least two weeks before considering ThermiTight in an area that recently had fillers.  The ThermiTight procedure can generate temperatures beneath the skin that may affect the duration of your fillers.