I hate how my body looks
Thats very unfortunate. Why hate how your body looks?
I'm not proud of the way I look on the outside, I was bullied a lot about my looks.
Since you have been bullied about your looks, you have allowed another person's opinion to get inside of your head. It is hurtful to not appreciate your own body. You should practive self-love and workout when it is convenient to improve your looks.
I need to go under the knife so that they all see that they were wrong.
Going under the knife isn't the answer. You can work on your looks without needing plastic surgery. All it takes is some commitment, effort and time.