I think this is one of most parents nightmares, Dawny.
I know it’s hard sometimes, but I think the trick is to try talking to them without going into shouting at them, explain, as you already have done, the possible consequences, chances are that she may not suffer any ill side effects, but, better to be informed of what could happen, than be left in blissful ignorance.
The police might possibly speak to them, as well as the school to make them more aware as well.
I’m not 100 % sure, but someone once mentioned to drink plenty of fluids to help flush the system out.
I can still remember the Leah Betts episode, she took an ectasy tablet, whilst out at a local nightclub and slipped into a coma, before dying. Sounds dramatic, but it did happen.
I’m not giving very good advice here, sorry, hope someone who knows a bit more will post and give you better advice hunny.