Totally know what you mean, and I've seen that look on people's faces, it's a hard one to swallow and move on from. I think this is one of the instances where I feel like I can reprogram my brain, just a bit. Rather than worry about how that person is reacting and how you just know they're gonna go home and be like "Hey everybody, I saw this person that couldn't talk, it was wild!" I try to remember how people really just move on with their day and never think about you ever again. I like to imagine them afterwards having thoughts like, "oh that was probably someone with a stutter. Hmm" and then they move on and never think about me ever again. I think about how I myself react when I unexpectedly see or hear someone with a handicap: it registers, there's a quick curiosity, and then I move on. Anyway, that's helped me.