https://pubmed.ncbi.nlm.nih.gov/15541093/
The iontophoresis machine that they tested in the two patients seems to be very different and is described as a drug delivery system (Iomed Phoresor II, which retails for around $700). It seems like a very limited quantity of Botox is required using this combination treatment -- in comparison to the 100 or so injections that are typically required when Botox is applied in and of itself.
If you know a friendly dermatologist, this method is worth looking at, maybe even using other iontophoresis devices.