Can I use derma roller (1.0mm) twice a month and can I use it on my nose even if it has blackheads?

So i just bought a derma roller with 1.0mm needle size and i just wanna ask if i could use it every two weeks? Is it also okay if i roll it on my nose which has blackheads in it? I'm 20 and I have this comedones since i was 17 and i also have a few on my forehead.