Kid, I'm so sorry to read that. I can relate to how you frustration could lead you to say that to her, I've been in similar situations with my own mother and other relatives before, even though I have a very close bond with my mother. I mean, I never raised my hand at her (though she has hit me as chastisement), but I've had very heated words with her in my teenage years.
Scratching you with her nails until you bleed sounds extreme, though, but then I can also sew how that would follow after you hit her back. I think your anger is justified... Just let it burn for a little while until you simmer down eventually. I think, if I were in your place, I would actually wait for your mother to come to you for a reconciliation if she feels the tiem is right for it. I know that, when my mother and I had had an argument, she would usually be the one to make the first move toward making things better between us.
Even though you're very angry with her now... it could also be helpful if eventually you apologize to her for smacking her, even if you feel in your heart of hearts that you were justified. Not only from a diplomatic point of view, but also for the sake of mending the now damaged rapport with your mother.
Hang in there, it gets better.
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clarity of thought before rashness of action