hi and welcome, I will send you a site that has photos of a cat being spayed and what the incision looks like afterward...if anything isn't right please take your kitty directly back to the clinic where she was operated on...there should be NO charge when doing aftercare...good luck.
http://www.pet-informed-veterinary-advice-online.com/spaying-procedure.html
Everyone of my girls has looked a little different after the spaying surgery.
If you have concerns, ASK your vet.