where's the undo button on facebook?

What to do when i embarassed myself on facebook!  It was no major thing, just i accidentally clicked join to an event i didn't want to join because the event already was over (Who joins an event when it's over! and ther was like only 4 other participants!).  So the embarassing thing is that the event maker will be notifyed that i'm explicitly joining his event which is already over.  Omg. hes gonna thing "well there's a proper fan of me! really" and next time he sees me he's gonna look at me extra carefully to se if my extra fan-ness is spotifyble. It will be, because i will remember this embarassement and start an uncontrollable blush.  Even though the one i was a particular fan of during todays event actually was his friend which was the reason why i even got close to that event-site in the first place, i just met that guy today and i wanted to see if i could find him on facebook.  I couldn't, bummer.  Or puh? at least there is a comfort he probably won't remember my facebook mess.  He probably was sceptical to join facebook because he was scared to do embarassing social mistakes (yeah, i wish...).  What an unnessecary eventful and stressful 5 minutes this has been.  Only two things to do now; 1 hope he (and nobody else) doesn't notice.  2.  Hope I can forget (i know i won't).  3 GET OF THE FREKIN INTERNET AND GO TO BED to prevent further embarassments, it's so late i long time ago lost control over my fingers. (4.  If that guy from the event is reading this because he's got extra time not being on facebook - here's a message for you; I'm really cute and want to meet you again)