Okay, you're 20 - you have not ruined your financial future at all, do not worry.

With the skin stuff, you need to see a therapist - you probably have dermatillomania or some other disorder. You can also lose weight, it will take a while, but you can do it!

For the scars, you could always see a plastic surgeon when you have the money to pay for it out of pocket. However, you don't need to get rid of those scars, I bet you look nice with the scars.

For exercise - start simple. I am not near your weight, but I was uncomfortable with the amount of weight I gained from a medication. I started playing Beat Saber 20 minutes a day, and I have lost 3 pounds in the last 6 weeks (Yeah, it isn't a lot, but it is something) without much of a change in diet.