hope it's not too late

I just saw your post and feel very sorry for your cat. I think you should take your cat to vet right away to get anti-becteria shot and some medicine. It's urgent to visit vet because they will tell you how to take care the injury later. Yunnan White Powder will only dry out the cuts and not strong enough. The vet visiting will cost around 60 dollars. Comparing to your cat's health, it's not expensive. Plus you need to know the feline AIDS and other fatal illness caused by cat's fight from your vet.
Take your cat to vet right away, trust me, it's worthy to do it!