Do antibiotics fight off Botox?

The antibiotic you are taking should not interfere with the botox. You may have another reason for the reason the botox isn't taking effect as expected. I suggest contacting the injector's office and scheduling a quick visit. Good luck.

antibiotics are medications that either prevent bacteria from replicating or kill them.  They do not affect botox which is a protein.

No. Antibiotics will not decrease the effect of Botox. Good question. There are some that may potentiate binding of Botox to the receptor, but, from my understanding, none will cause Botox to "not work" 

It is unusual for Botox to be rendered less effective with anabiotics Sometimes anabiotics can render Botox more effective.

I do not know of any medications that reduce the effect of Botox.  Sorry about your experience but I don't think it was the antibiotics.