Check and see if it's allergies....skin allergies...or food allergies....and I would strongly suggest getting a second opinion on what kind of spay job was done....Sometimes a not so good vet may have done a crappy job and left something unattended to....Talk to your vet about shaving her present hair down to a healthy minimum and starting a new doo...just to get rid of existing skin problems and irritations.....hope it gets better....keep us posted....