Please share some whitening care tips.

Does age affect facial whitening as well?
When I was young, I didn't know about things like sunscreen, but my face was fine.
Lately, even though I apply sunscreen before going out, I am getting freckles and blemishes, and I can see something dark and patchy.
It may not be solely due to UV rays, but it is to the point where whitening care is necessary.
How are you all doing?
Do you receive a separate prescription for back care?
Do I need to go to a dermatologist?

Since I saw the challenge post, I’d like to know a little bit about it.