The nurse you trust would be a great person to tell! She cares about you and will want to make sure you are safe and protected like you deserve to be.

You're right, it is scary to tell, because you don't know exactly what will happen, and we don't know enough to say. But consider the fact that staying in an abusive situation is doing scary things to your mind and body. Your brother's too. He deserves safety and protection as much as you do.