Facial rash after Botox

Yes, it is possible. A reaction like this can occur after a Botox injection. Having a small amount of the Botox injected to the volar(smooth surface of your) forearm could rule this in or out.

Having a rash from Botox would be very unusual and I have never seen it. I would look into the topical, the gloves, or the preservative in the saline used to mix the Botox. I would do the Botox next time without topical and with latex free gloves. If still a problem, use non preserved saline in the Botox. You can also test the forearm with the preserved saline, latex, and the topical.