Stuff happens. The longer you live, the more likely that bad stuff will happen to different parts of your body.
And yet, sun damage can be healed to some extent: people wearing sunscreen for a year found that their skin has improved. It was not the sunscreen per se that did the trick, but it allowed the skin to heal while the sunscreen protected from further damage.
Your brain can stay younger longer if you exercise.
Exercise can help with muscle and arthritis pain.
Exercise can even help with chronic pain caused by unknown factors.
Even damaged nerves may heal after damage.
But what you can’t do with impunity is to keep damaging your body and expect that it will survive the mistreatment.
What would you say is they offer you to apply 40% hydrogen peroxide to treat a minor skin condition? Say no. Say that hydrogen peroxide is a strong oxidant that will produce other damage, the equivalent of cutting your nose because you have a cold. What about 2% hydroquinone? Say “no” again, because you will feel silly if you later get ochronosis (permanent hyperpigmentation).
And say “no!” to eroding your skin to nothing in the pursuit of “glass skin”.
Take care of yourself and remember that there is nothing worse than feeling like a fool for hurting yourself when trying to fix a minor flaw.