media output and microphone not working

Ok basicly I incorrectly wired an aux port to my car stereo and pluged my nexus into the audio port. Ever since my mic dosnt work and my media volume dosnt work. My speakers will work if the phone is rang but not if I play music etc. If I use headphones I can hear media volume and also use the mic on the headphones. I'm not sure if I've destroyed the headphone port with stray voltage from stereo or if the phone is stuck in headset mode any ideas people!!??