How will a premolar extraction affect my face?

I'm a 21yo f. A year ago I got braces on the lower teeth for which I had to have 2premolars extracted. I noticed my face got thinner. Now my ortho wants to start treatment on the upper teeth, for which she wants toextract a premolar. Same premolar on the other side was extracted as a kid when it started to come out from roof of my mouth. My face is quite asymmetrical with my nose, eye and mouth all resting on the side w/ the extra tooth she wants to take out. How can this affect my face? Thanks