You can moisturise the skin by drinking water.
Water is key when it comes to skin health, but it only becomes noticeably visible on the skin when you are dehydrated. The skin needs you to add moisture from the outside to allow the barrier function to work correctly, otherwise moisture will just evaporate away.
If you have oily skin you don't need to moisturise.
Oily skin still needs hydration because if it feels dry it will
over-compensate by producing more sebum, which makes it feel even more oily.
You should choose skin care for your age.
Patients in their 50s May have exactly the same skin concern as a patient in their 20s. You should always choose skincare by your skin type and concern... not age! I recommend having a face to face consultation with a professional rather than seek advise via the internet.
You won't tan if you wear sunscreen.
UV filters make up a third of the protection against UVB rays, which affect your melanin production. Sun protection doesn't completely stop a tan - it just slows the rate at which the skin darkens, which is a good thing.
Blackheads are pores filled with dirt.
A blackhead occurs when a pore becomes clogged with sebum and skin cells.
The reason the pore is black has nothing to do with it being filled with dirt, but is an effect of the keratin in the sebum plug having oxidised.