E.K.
You don't say how old your daughter is? So I assume she is to young to talk to you about what she may have swallowed? I would probably be freaked out too. 90% chance that if she swallowed it, that is "passes" safely. But that still leaves too much of a chance that some edge of the barrette could perforate her bowels. The worry would drive me nuts and the $100 co-pay for the ER to xray her would be a small price to pay to relieve my mind.