How to get out of a HUGE lie?

So I told my parents for no reason that the cops and the security at the my school came to my school and searched me for drugs because somebody called the Drug Hotline and said they saw me doing drugs. This is completely untrue and I have never gotten called out of cl for anything to do with this. It is extremely deep into the lie and now my mom wants to call the school and ITS A COMPLETE LIE. I don't know what to do because if i say i was lying then i look like a pathological liar.