I have finally realized that I am a bad person.I don't have a big heart and I hurt people unintentionally and intentionally.

I am rude quite often and lack meaningful connection.
Every day I do something I regret later and I have hurt people's feelings.


How can I be a better person?

I don't think you had a good role model, if what you say about your mother is true.
So do what I have been doing for 68 years: examine what happened, what was lacking, and what you can change in yourself. (And drop the 'bad person' bit - it goes nowhere.)

You seem very preoccupied with looks, which is normal in teens, but should be replaced with life quests and careers and plans as you get older.
Your mother says ugly, others say attractive, NONE of that matters as looks fade. I had a cute face when young, and a blah body, but that meant nothing - my mother put me down about everything. Through my 20s, 30s, I learned to carve out a 'who cares' attitude. I didn't like classically attractive men anyway. 'Regular' guys appreciated me more. I appreciated them more. Let all the beautiful people have their mutual admiration society.

I prefer learning new things, and maintaining long term friendships, to anything else in the world. What do you want to do with your life?