Earphones mic not working on MacBook Pro

So I bought my 15'inch MacBook Pro in late August 2012, and it at first COULD detect my Apple earphones mic. I have also checked in the System Information that it can detect Apple earphones mic. After a few days it became very hard to stick my earphones in the headphone port, and near the headphone port it had bumps like when heat burns up plastic and it expands. And when I manage to stick in the earphones now it cant detect my mic although it still send noises through the headphones. Why is that?