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I have discussed your concern with our team Gastroenterology Dr. Ratnakar Kini. It is highly UNLIKELY that the activated charcol would interact with the injected Botulinum toxin to cause any reaction / side effect / spread the toxin.
The persistent nausea and upper gastro intestinal symptoms could be from gastric irritation due to the activated charcoal itself (if you there is repeated usage) or alcohol. In rare cases it could be manifestation of something more serious like a Pancreatitis.
You may take a anti ulcer medication like OTC Prilosec once a day for 7 days. Avoid alcohol , spicy and irritant foods. If the symptoms persistis you may require further evaluation.
Hope this helps
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