I would have added (calmly and with a genuinely friendly smile): "OK, I sometimes say things which don't come out right. It's how I'm wired. The way you looked at me now tells me I should probably have said something different. Wanna tell me what you thought so I can do it better next time?" (or if you can say that in a shorter way, even better -- I am very long-winded.
I learned from friends and from my mother that if I express embarassment, but with a laughing-at-myself smile, it is easier for me and also for the other person to get through (or even work through) the uncomfortable moment. In some situations I even literally say, "Oh nooo! I feel so embarassed!" and laugh, and it helps a lot to break the uncomfortable tension.
If you just stand there and blush, or freeze up or get upset, the other person doesn't always know what to do next. Everybody feels uncomfortable, but no-one breaks the tension. Occasionally saying what you see and asking what it means can help a lot. Outsiders like us weren't there to read her face and to give a good opinion. Besides, we're a bunch of aspies, so we might not have known either -- and nor would a neurotypical person necessarily have known without asking.
Some examples of shorter ask-phrases (for someone who doesn't know you have a problem):
"Hey, I'm not good with body language. Mind sharing your thoughts?"
"I struggle to figure out the simplest things sometimes. Can you explain what you mean by what you just said?" (Ifit was something spoke that confused you.)
"I feel silly saying this, but I didn't understand what you meant there."
"Help me out, my social skills go on strike sometimes. Did I say something bad?"
And so on. Always in a friendly, non-intimidating way, so that the other person does not feel burdened by your problem, but rather a little amused in an endearing way.
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When I must wait in a queue, I dance. Classified as an aspie with ADHD on 31 March 2009 at the age of 43.