Oh dear. Sorry to read this. Did the bite draw blood?
They're getting hormonal as they are growing up, and although sows are generally ok with each other sometimes they do fall out. I had one fall out with her herd....
I'm not insinuating that they live in a small cage/hutch, but expanding their environment and giving them more space can sometimes resolve things, as can giving them one each of everything (e.g. if you have one hiding-house in there, put two more in for one each, have three food bowls etc).
Do they have plenty of run-around space each day?
If you feel they may fight again and draw blood then it would be best to separate them. Have you got anywhere else to place either the victim or the aggressor? The aim is to leave the two pigs who get on the best and remove the other, with the hope to find her a partner that she gets on with. Rescues can help with that.
I'm tagging
@Wiebke who has more experience with bonding issues than I do

xx