My 15 Year Old Daughter Accedentially Swallowed A Needle. I

My 15 year old daughter accedentially swallowed a needle. I took her to A&E and they preformed an xray on her throat and abdomen but found nothing. They said there was nothing they can do and if she flet unwell to come back. I'm worried if that needle is in her and they couldn't see it in the xray and what harm it can do.