Is this fair? Mom, sister and fitness gram?

My sister is a little overweight. Well, we got our fitness gram papers back today, and my mom let my sister put her hands all over my report, but when I asked to see my sisters papers, my sister whited out her weight. Is this fair? I rarely make fun of her, but she always calls me ugly, and my mom doesn't stop her until I say something, and she's allowed to come in the room at my dermatologist appointments (I have acne and acne scars) But if she has to go to the doctor, I have to sit in the waiting room! I'm hysterical crying because it's not fair! When she measures herself on the wii fit, I have to leave the room, but when it's my turn, she stays! Why do they let her get away with all of this?!?