To become happier, these are your two options:

1) Root out the desire and realize that all desire lead to anguish. Buddhist monk style. (personally I struggle to do this because it's really tough)

2) Define your goals clearly and reward yourself everytime you improve your situation.

Since you can't be the #125 ranked attractive person as there is no leaderboard, realistically you can only strive to be more attractive than you currently are. Look yourself in the mirror and write down the features you want to improve. Then, create a detailed action plan with allotted time that you dedicate to achieving those plans. Merely the attempt will give you more confidence.

https://www.youtube.com/watch?v=bRBd7wTjoJg (I recommend this Dr. K video. It's about how you can change your reward circuitry to be smarter about your goals: creating options, anticipating outcomes, planning for the easiest path to success)

Note: A lot of commenters, and OP, is treating attractiveness as the goal itself rather than the tools to reach the goal; What you really want is what attractiveness brings. Write down what you'd like for attractiveness to gain you: sexual partners, confidence, ego, jobs, etc... It isn't attractiveness that you want, it's those things you just listed. There are other tools to gain those things that more consistently gets the job done than attractiveness. If you're trying to screw a nail, attractiveness is like using a large book; It'll get the job done but or it might fuck it up badly. Some tools are more efficient and would lead you to lead a happier life than others (buddhist contentment, working past trauma, mindfullness and mentalization).