Hi Mary, and welcome to the NSDA BB - thanks for joining us.What you describe has been reported as a possible consequence of a Botox shot - but doesn't seem to happen every time, or to every person.
When you say flu-like symptoms, do you mean the full 'aching bones, headache etc', or something less, like a sore, raw throat? I've had Botox shots more than 40 times now, and I certainly experience the raw throat at times - usually in the first week after the shot. It confirms to me that the shot has taken.
It sounds like you may have been given a fairly high dose if you were 'aphonic' (no voice) afterwards. It takes a while for you and your doctors to arrive at a treatment regime that suits you, and you may need a lower dose next time. My advice would be to stay with it - subsequent shots usually last longer, and you should get better relief with some adjustment. Ask your doctors questions - what dose are you getting, are you getting the shot unilaterally or bilaterally, how many sites are they injecting per vocal cord? It helps if you are an active participant in your treatment.
Good luck, and let us know how you get on.
David Barton (AD/SD, Auckland, New Zealand)