New cat got spayed 12 days ago, looks very strange?? Is it infected? Help??

Our new girl Dite,(they say she's 2yrs but she's so skinny n small) was spayed Feb.11th shortly after the humane society took her in, we picked her up almost a week ago and today is the first day she's warmed up to us and given us all the love and I was finally able to look at her incision.. And it almost looks infected? It's a Sunday so we cannot call our vet, it's either the emergency vet or wait till tomorrow morning. The purple looks like a bruise, the tan skin part looks like gauze sticking out?? She is drinking eating and using the litter box, plus she's being so affectionate now that she feels safe with us.