Could Botox be dangerous?

[Squintyno]

I Am considering Botox for more medical reasons. I have a significant eye squint which I am informed by my dr can be corrected significantly with Botox.
It is very much affecting my life, also my self confidence. It looks odd, affects my vision and is getting worse.
My issue is despite the fact that Botox is everywhere , I am very risk adverse and suffer from anxiety. I have stupidly read horror stories online of Botox causing autoimmune diseases, the fact that human plasma is used causing blood illnesses. I wish I could get a definitive answer. How do so many people easily get it when it warns that it could spread and stop breathing.
I hate my eye squint but also am freaking out about putting a neurotoxin in. Obviously the dr spoke about the risks but said they were small, I just wish there were no risks .
Does anyone get it for medical or cosmetic reasons who could reassure me?