If I have a nabithian cyst why does it come out and go back in? Also is that bad that I have one, is it something serious?

Benign condition. A nabothian cyst is a benign mucous filled bump on the surface of the cervix routinely discovered during a routine pelvic exam. It is caused by build up of secretions when glands on the surface become plugged. No treatment is necessary. Nabothian cysts do not cause any problems.