If I manage my stress better + sleep, will I start looking better?

I've had generalised anxiety disorder and other anxiety disorders since a young child, and just also feel very stressed all the time. I'm only 21 but it feels like I just look tired already. I really try with skincare and avoid the sun and always wear SPF 50+, especially since I live in Australia. I've had problems with sleep for a long time too, at one point I was doing super early morning shifts for some time too and I feel that really worsened things. I think I could probably do with some weight gain (a slight bit) too, as I struggled with eating enough due to mental illness (depression I think impacted it a lot too) and then was getting a lot of exercise from my job (cleaner). I just want to know- if I'm still young, can I bounce back a bit? I've been really trying my best to eat more + healthy, trying but maybe failing with stress (yes I see a psychiatrist and psychologist etc), and have definitely improved with sleep really recently, but not enough and am going to go for a sleep study.