Acne hole on nose

I had an inflamed zit on my nose and which popped after rubbing my nose too hard. Now I'm left with a little crater in the middle of my nose. But every now and then, the acne hole starts filling up with whitish/grayish material and hardens into a little dimple. The stuff stays put unless I pick at it because I think it's just accumulation of dried skin; but I'm not entirely sure now because none of the ice-pick scars on my cheeks ever fill up. Does anyone know what it is?

Another thing, has anyone had success treating acne holes on their nose? I've searched around the board obsessively the last few weeks and the general opinion is that indented nose scars are not treatable. Is this true? If so, are there treatments that might make them more shallow?

Oh and one more thing related to my first question. My mom says she had acne until her mid twenties and was left was many indented scars. However, over time, she claims that the indented scars have filled up on their own. Now in her late forties, she has a decent complexion in that she doesn't have any noticeable scarring. Is my mom speaking the truth or is she just trying to help relieve my low self-esteem? Is it possible that what builds up in my acne hole on the nose perhaps skin tissue rebuilding itself?

Thanks