Don't panic yet!
Get a plastic baggie and carefully scoop what you can into it along with the more solid poop. You will want to bring it to the vet for tomorrow. That will be for a parasite check.
Very, very carefully, check the snakes vent. If it was a really big poop, she may have strained a bit. Sometimes a little blood can happen. Check to make sure there is no more bleeding.
If there is anything fleshy sticking out tho... we have a bit more of a complicated mess and the snake will need to see a vet.
As a precaution, keep the snake on damp paper towels for a few days an keep an eye out for any prolapse from the vent or more icky poops.
*edit!!*
Keep the little poop sample in the fridge overnight