if it is too tiny, you’ll have to feed with a dropper. You can get kitten milk at Walmart
It will have to be fed multiple times a day until it is mature enough to eat hard, kitten food.
Just raised our second 4 in 17 years from very small babies to nearly grown-up cats. It is work, but fun.
Contray to popular belief, cats are loyal, friendly and make great companions.
Eye dropper, slow. Warm the milk to room temp. If you have a heating pad put it on low with a blanket over it and lay the cat on it. This works for puppies too. I rescued a grey tiger stripe that I thought was froze beyond saving. Shes my house mouser and a pain in the arse. No mice has a price. Good luck.