i dont see a picture

That any better ?

this is my take on it. It looks like a post acne mark (hyperpigmentation) left by your acne. If you were picking on it, it might had caused the discoloration on your nose. These arent suppose to be permanent but sometimes they take a very long time to fade for numerous reasons.

Being out in the sun will prolonge the mark and will make the acne mark darker so use sunblock if u go outside. I suggest you do some research on how to treat acne marks to have a general understanding of it or if you have one, talk to your dermatologist.

Also to make sure its not an acne scar, check the texture of the marks on your nose. If you can feel a pit or a hole in your skin then you have an acne scar.

I cant feel a pit. How deep would it be ?