Where I live 'getting fit' means exercising/healthy living but when you write about surgical procedures I'm not sure if you mean something different.

I think exercising and healthy living is a good thing for anyone, and there's lots of evidence it boosts mental well-being too. I'm not sure I would say it would improve your personality, but maybe your self confidence.

As for cosmetic surgery, I have no experience of that so can't really offer an opinion.