Can you take a photo?

Make sure the yolk stays WET. I'd put it back into the incubator at 100% humidity.

I have heard of people who tie of the umbilicul chord, and then take the yolk and feed it with a syringe to the hatchling down its throat. I have never ever done that, so I can't advise either way. It may be worth looking into though.

for now, make sure it stays wet. once the umbilical chord dries out, it's impssible for the snake to continue to feed off of the yolk.