Prosopagnosia is something that I have two different diagnosis of.
The first was IMO, a very unprofessional cookie cutter paper trail type diagnosis.
According to that one, I am face blind, (and a very long list of "others") although I can recognize people after the third or fourth meeting, rarely the 2nd, and never if only seeing someone in passing.
However upon a much more lengthy detailed and intense study of all the contributing factors to my personal condition, it was decided that the fact I don't look at peoples faces with any interest. I was asked what color his secretaries eyes where, I was asked with his back turned to identify his nose and mouth from a chart, I was asked to pick a sketch that looked like his intern. Passed with flying colors, though his secretary was of extreme interest to me, and his intern was a tease and laughed alot, and I have known him for quite some time.
I can recognize people in other ways, even at great distances, by their movements. Up close and personal interactions do not involve me looking at their eyes or mouth, until I am Very comfortable with that person. But if I see a person that I kinda know, I can spot em at the other end of large mall, or football field pretty accurately, by the way they walk and move.
What I see initially is a distant figure when talking to someone new, not necessarily blurry, just distant as in no detail. Kinda like a light is shinning from behind them, or like looking at a star, you know there is detail there but you don't spend much time or attention trying to figure it out, I spend my time thinking about what is being said and how I am going to respond, and of course running through three or four possible scenarios of each before responding, so who has time to map out an image when all is preoccupied with much more important stuff.
Hope that gives you a general idea,
it really is hard to explain what the rose in my front yard smells like exactly, like a rose yes, but all roses are different, and some don't have any smell at all.