What are complications associated with getting a botox injection for an abductor contracture?

Bruising & soreness. Botox (botulinum toxin) inhibits the neurotransmitter acetylcholamine, so the nerves can't tell the muscles to move and they're paralyzed. The effect lasts 4-6 months. Injections can be associated with bruising and soreness at the injection site.
Botox contracture. If a scarring condition causes a conracture, then Botox may not help if the muscle is not contracted but the dermal collagen has been produced in more quantity. Furthermore, if Botox is injected into a muscle, even if it is in spasm, and the Botox helps reduce the spasm, it may inhiibit important functitons of that muscle for up to four months!