Does Fraxel work on stretch marks?

Yes. Fractional Laser (also trademarked as fraxel, a type of fractional laser)  has recently been FDA approved for the treatment of stretchmarks. It has been shown to get rid of stretch marks, and it's also been shown to treat many types of scars.
 
None of the above is not intended as medical advice. If you have a medical concern, please consult your doctor.