Kendall Jenner's Billboard Music Awards Teleprompter Disaster -- I Can't Read

Kendall Jenner was doing just fine during her introduction of 5 Seconds of Summer during last night's Billboard Music Awards ... when suddenly words became her enemy and the whole thing went to hell.

Jenner got through the first part without a hiccup, but suddenly got thrown off track ... which led to her blurting out, "Guys, I'm the worst reader!"

Jenner took to Twitter afterwards and seemed to blame her eyesight for the debacle, writing, "Anndddd as if I wasn't nervous already!!!! #NeverLeavinMyContactsAtHomeAgain! #LOL #LessonLearned"

Better luck next time.