Your mucus plug can grow back. But with the back pain I would call triage and see what they say xx
You’ll know if it’s your mucus plug, mine looked like someone had cracked an entire egg in my knickers!
Just call them, better to be safe 😊 my mucus plug was massive, like blood jelly.
Only need to call hospital if waters break or when having contractions every minutes or less that last around a minute and they are regular. Also if you are concerned about babies movements. Sounds like it could be the start of early labour. Obviously if you are concerned than call the hospital x