My iphone won't connect to itunes? - 5

So my friend asked me to put music on her phone through my computer… So i connected her phone to it and accidentaly set it up so it thinks that her phone is my phone. Now when i connect my phone to my computer it shows that no phone was connected under my name or anyone elses. I have a trip tomorrow and need to fix this as soon as possible. Please help and ask questions if there's confusion about what happened!

Hopefully you didn't leave for your trip already, but what I can tell is that you need to delete your friends phone from you computer, usually when you hook it up it "syncing", that's when you hover your mouse over the phone or it should be a arrow thingy next to it and you can press delete if that doesn't work you go to iTunes setting and it should show you a listing of all the owned devices find your friends phone and delete it.