Yes - I have same Skype bug - but if you set Skype to the ‘default’ mic, I find that works.
You may also have to set your USB mic as the ‘fall back’ input device in pavucontrol
Some sample menu selections
http://thumbs2.imagebam.com/56/ae/96/87e8ea695953063.jpg](ImageBam)
Sometimes my USB mic is there in some - sometimes not. Select the ‘default’ if not there
http://thumbs2.imagebam.com/4f/3b/96/c45922695953083.jpg](ImageBam)
Again - note what I suggested wrt pavucontrol
Yes - but don’t give up. Let me know if my suggestion works.