There is no such thing as a warrant being "over and done with". They don't ever expire.She swears that she is clean, that she thought that her warrant was over and done with. I am thinking that she still has a warrant out there.
Your friend needs to get herself an appointment with an attorney, so s/he can negotiate the terms of her surrender on her behalf. An attorney may be able to help keep her out of jail.
Strolling on down to turn herself in without benefit of counsel is not a smart thing to do, and "throwing yourself on the mercy of the court" is something that only works on TV.

