Pyridostigmine is a drug that prevents the body from breaking down the chemical mediator (acetylcholine) that causes muscle contraction. Given botox works by preventing the release of acetylcholine, it makes sense that by preventing the body from breaking this hormone down, more of it is around to activate the muscle.
Put simply, pyridostigmine increases acetylcholine levels to counteract the botox effect of decreasing acetylcholine leading to a net zero effect theoretically. But does it work that way? According to one research paper, it certainly appears to do so!
In less dire situations, simply starting a patient on pyridostigmine 30 mg 3x per day without an initial loading dose is sufficient.
Otherwise, behavioral support alone is recommended for less severe botox side effects.