How to deal with a family member constantly being rude to me?

My younger sister has been rude to me for a long time now. She has made fun everything including my looks, the body, the way I dress, the college I attend and my friends. She makes fun of the college I go to and says that I am a failure, will get nowhere in life or get job opportunities because the school I go to isn't "prestigious" in her opinion. I am 19 and currently live at home and she constantly shames me for living at home and says I should move out. She compares me to influencers who are my age. She would show me pictures of influencers my age and say things such as "Oh she's so much prettier and successful than you. You are doing nothing". She always says she is prettier than me and that her looks are better than mine. I have always had scars on my legs, and I have been visiting the dermatologist for this. My sister says hurtful things such as "Ohh eww what are those things on your legs?? I do not have any, see my legs are clear. Maybe if you shower they will go away". What she said has made me so insecure that I have not been able to wear shorts or a dress this entire summer. Last year, I went to a concert and before I went to the concert she saw my outfit and gave me the most disgusting look and said "Ohhh...that's what you're wearing??". This ruined my entire mood and I was upset during the concert. On many occasions, she has made harsh comments about my friends' looks and personality. I am really frustrated and I do not know what to do. I have told my mom about all this multiple times but everytime she gets annoyed at me and says that by venting to her I am just stressing her out and disturbing her peace. All these things she says just makes me feel so bad. I am not sure how to navigate this situation, so I am looking for advice. Thank you.