Hey,i'm 20yo male and today i noticed some brown spot on my back, it kinda a circle brownish and feel kinda dead and dusty and its flat,am abit worrid?

It is difficult to: say what this is without seeing it. It could be a mole, a patch of dry skin, eczema, or possibly something else. It would be best to have a doctor look at it. If you are on HealthTap prime, you can do a consult with one of us and we could look at it and likely diagnose it and give you further advise. Your own doctor could do the same, so I recommend you do one or the other.