If you have a hernia in your belly button the hernia in the belly button is not dangerous itself but if you leave the hernia in your belly button untreated it can lead to a serious infection.
The hernia in the belly button can become trapped and if it does then there's a high chance that it can cut off the blood supply to the contents of the hernia.
If that does happen it can cause life-threatening conditions including things such as gangrene or peritonitis.
If that does happen then the hernia in the belly button becomes strangulated and it's life threatening if it does have the blood supply cut off to it.
So I would highly recommend going to urgent care or see your doctor as soon as possible about the hernia in the belly button.