I accidentally sent a voice message in a group chat and im really embarrassed?

I have an iphone 4s and I was in a group chat with my 3 friends on imessage and I accidently sent a really embarrassing voice message of me speaking in a American accent and when they asked me what that was I said that that was my friend and I was on facetime to her and they believed me because the recording didn't sound like me but its so embarrassing, I deleed the message but they hears it anyway and I feel like they will be teasing me about it and ahh im so embarrassed. They haven't said anything bad about it but one of my friends saved it, im so scared to go into school tomorrow. What should I do? Im so scared. I know that this might sound rally stupid and not embarrassing but to me it is and im literally crying omg. What should I do? Im pretty sure they will listen to it again after school and say that its me(it is me but I said that its my friend) im literally so stupid for sending it. Please help
Added (1). sorry about the typos. I typed that really fast.

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