Lilly's was puffy for quite some time after her spay. I took her in ummm I think 4 - 5 times worried about it
. Each and every time I felt like an idiot because the vet always gave the same response "looks great, she's healing fine!" and sent me on my way. I even took her because I thought there was something stuck in it. I felt like a dorkkk but I was always so worried. I'm sure Fiona's is the same but to ease your mind, you could always just take her in quickly. I'm almost 100% sure that's what it is. My vet didn't charge anything, not sure how yours is though! Good luck!!