ABANDONED. Fantasy novel about a human witch's familiar

[Jessica]

About 10-12 years ago i bought a book almost at random from walmart by a new female author. I dont remember very many detail, but here is what i do remember:
There are 2 main female characters one is a witch and the other her familiar. The witch turns her college best friend into her familiar after getting here drunk so she agrees to the terms and conditions of being a human familiar.
They go on some sort of journey (i dont remember why) and end up at some sort of witch's summit. While there the familiar is tortured by another witch while her witch tortures the other witch's familiar too see which familiar lasts longer to prove the witch's strength i believe. The other familiar is male and he is tortured by thinking and feeling like he is being eaten from the inside by rats.
Any help is greatly appreciated, thank you.

[Kris]

Jessica, please post a new comment if you're still looking for this book - or if you found it.

Jessica (OP) was last active on the site in March 2020. Moving to Abandoned folder.