I'm glad she seems to be ok! I don't know anything about dumb cane, but a quick check of wikipedia
https://en.wikipedia.org/wiki/Dieffenbachia
suggests the symptoms are temporary, and it sounds like she didn't eat a large amount.
"The common name, "dumb canes" refers to the poisoning effect of
raphides, which can cause temporary inability to speak; for this reason it is also known as the mother-in-law plant."
"The
cells of the
Dieffenbachia plant contain needle-shaped
calcium oxalate crystals called
raphides. If a leaf is chewed, these crystals can cause a temporary burning sensation and
erythema. In rare cases,
edema of tissues exposed to the plant has been reported. Mastication and ingestion generally result in only mild symptoms.
[9] With both children and pets, contact with dieffenbachia (typically from chewing) can cause a host of unpleasant symptoms, including intense numbing, oral irritation, excessive drooling, and localized swelling.
[10] However, these effects are rarely life-threatening."

They sure know how to worry us, don't they!