My cat gave birth to 4 kittens 1 died she would not rip the sack I had to do last 2 .She chew cord on too and I think was just to tired to do the last I tied the cord with dental floss.However I see a small bubble now before the cord not sure what to do and the vet is closed.Any help would be appreciated .

It sounds like your kitten is going to have an outy belly botton. Should be fine till you can get it into the vet to check.

This may or may not be a problem.
I obviously can't tell you without seeing the kitten but you definitely need to get her o a vet before she is rehomed to make sure it doesn't herniate.