Don't worry. We shouldn't have animals if we aren't going to worry about them or baby them and spoil them rotten!!
I would be worried about it too.
When Keegan was spayed, I brought her home on Friday, and Saturday when I got home she had gotten sick all over her crate and had diarrhea. Then on Monday I noticed her incision was lumpy, I thought she might have herniated her incision. So I called them and they had me come right over and said that it was just scar tissue where she was so active.