I think it depends on how much you value your friendship with her, as long as her lies don't cause you any problems, and she is harming no-one perhaps it is best left alone, ask yourself how much it bothers you? and if you can deal with it.
However i too had a friendship with someone like that when i was young, it was devastating, this person caused so many problems with her lies,that i ended the friendship for good, and i certainly would never go there again, just be cautious is my warning to you, good luck.