Will Antitoxin stop negative effects of forehead Botox injection?

Your reported side effect of chest pain, accelerated heart beat, sweating, diarrhea, are all part of anxiety and have not been reported with Botox injections.  A review of the literature and reported cases indicate that risk of developing systemic effects is related to injections of greater than 600 units of Botox occurring every three months.  THIS DOSING IS NEVER DONE IN THE FACE.   This dose of 600 units is only injected for muscle disorders and is not a cosmetic procedure.   When this very very rare side effect occurs for muscle medical conditions you would experience mild generalized weakness, and not the symptoms you have described.  
The most common side effect from Botox into the face using the average dose of 50-60 units is a headache.  These do not last more than a few days.
If your symptoms persist, you will need to see your Primary Care Physician for management and also see the injector so they can evaluate you.  I hope you feel better!

There is no antitoxin and your symptoms do not at all sound like they are due to your injections.  It may be an anxiety reaction so see your family doctor