If your brother makes you angry or upset again, maybe try just saying something like, "I don't want to talk about this right now" or "I have to go to the bathroom" (even if you don't really have to, a little white lie would be okay if fighting/familial strife is a possible outcome of sticking around) and then go to a safe place like your room. When my older stepbrother and his wife were fighting over playing Taboo one night when they were here for Christmas, their fighting made me uncomfortable so I told everyone I was going to bed, said goodnight to everyone, left, and everyone was okay with it.
If you've escaped the situation but still feel mad, try beating on a pillow or even venting here on WP, like in The Haven forum or in the "Something that made you UNHAPPY today" thread in the Random Discussion forum. Other people might post who can help you.
Or talk to your mom or dad about it.
By the way, how are you feeling at the moment...physically, that is? It sounds from your original post that your brother really roughed you up.
Hope you're feeling somewhat okay now.
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I wish Sterling Holloway narrated my life.
"IT'S NOT FAIR!" "Life isn't fair, Calvin." "I know, but why isn't it ever unfair in MY favor?" ~ from Calvin and Hobbes