Mac book screen light?

I think the light on my new(ish) Macbook… the one that makes the screen brighter while not in energy saving mode… has gone out. I can still see the screen fine but it’s just a little bit darker like the screen looks when it hasn’t been used in a few minutes… have i possibly slipped into a strange computer setting or is my screen simply deficient? Should I just call in the spoils of my Apple care?