Cant tell without a picture.

If its red and flat with no opening, its a mark

If it looks dented, or like an open pore its a scar. Hold your head under various lighting, use a torch and you will see the texture of your skin

After my pimples left they left me this

Now I want to know if they are scars or marks because they don't seem to have depth to them and if they are scars will they turn deep? Because my skin feels smooth there so idk.

Oh that? Yeah that is so obviously a scar. See scars are the sort of indents/deformities of the actual texture of the skin post-acne, while marks are just, well, redness on the surface of the skin. Marks would be over smooth skin that has regular texture. But you? Judging from THAT, you know, that thing you just didn't show us? Yep. Classic scarring.

....seriously man?

I'll wait for the gears to turn.