Reaction to botox for laryngeal dystonia--prolonged hoarseness

I have been getting botox injections for about 15 years to treat laryngeal dystonia, and the shots have been great until recently. I typically have had a hoarse or breathy voice for about a week (+/-) after getting the shots, but I have had prolonged hoarseness after my two last injections. At the time of my last injections on May 29, my doctor commented on a thyroid nodule and recommended an ultrasound, which I had done. Following that I had a needle biopsy, which produced indeterminate results. Further testing is now being done. I have asked my doctor if the nodule might be causing my hoarse voice, but he does not think that this is the case. He does not think that the nodule is big enough to cause this. Anybody have any thoughts?