I can see how its a neg. Kind of like the eye crusty thing or picking off a piece of lint on their shoulder. I personally wouldn't use it. However, since its your idea you need to be prepared for when she says No. Some responses I might use are.
PUA: Did I just see you pick your nose?
HB: NO
PUA: (Saying smiling in a cocky funny tone) I bet your one of those people I see when I'm sitting in a red light digging in their nose like there is gold in there.
Then just move on to something else but I hope this helps.