
Back on boxing day last year, I had a big fight here. Four dogs involved, two wounded. One had a 1.5x1.5" triangular flap on her leg, through a couple of layers of tissue. With daily bandage changes and hibiscrub, it healed very well, and there's just a faint dent in the fur now. The other had a deep puncture in her leg where a canine tooth separated muscle layers. She did have to go in but only for antibiotics; the space between the layers was the issue.
If your girl's cut gets infected then I'd take her in, but if it appears to be healing well and it's closing up, I'd not worry. I'd keep bathing it with either dilutes hibiscrub or mild saltwater.