Good luck.
Corn snakes do start out awfully small, and when they don't eat, they only get smaller
I call them little shoestrings.
I remember when I first got my cornsnake as a baby, I had never owned a snake, and I looked at her and thought, "What in the world can I find that is little enough to FIT down your little mouth?"
Extra small pinkies was all she could have.
Again, good luck, and good on you for trying to save it. I hope it works.