Mic not listed in recording tab of sound in control panel

I recently got a USB headset setup. It wouldn't seem to work with my internal mic. I disabled the internal mic under the recording tab in sound in the control panel. Once I did that, the headset started working. However the internal mic is no longer listed in the recording tab. Does any one know how to get it listed back in the recording area of sound, so I don't have to use the headset all the time?