I need help

Believe me, anything you said to a kid will be planted in her head and she'll hold onto it. I grew up as a girl who is always insecure about her life because I've been told that I'm ugly since I was a kid. Even if it's just a joke that my bigger sister did but somehow I've already planted the thought in my head. I grew up never believe that I'm beautiful the way I am. I always thought that I'm the ugliest person in the room. Sometimes the thought is killing me.