what to put on my skin: YES OR NO?

[RRM]

But in the wild we surely get direct exposure.

Yes, and their skin is generally very wrinkly.

And what about African people? Their skin will age faster than us?

the more direct sun exposure, the more aging is accelerated,
though the high pigmentation in dark skin is a protective factor.

Regarding the hair itself or the skull?

Regarding the skull, but harsh chemicals and high mineral also dehydrate hair, making it break sooner.