I think you were both friendly.
But she was ott by touching your Dds head.
Also she was handling food, so stray hairs that may have fallen off would be on her hands! Elfandsaftey innit?
Seriously, I wouldn't give her feelings another thought.
She moved tables in order to manage her own stress about the situation.
You had your lunch without further incident... All good.
You don't have to explain your Dds medical history to anyone: a simple "she doesn't like" that sounds prefect. Not everyone knows what "sensor disorders" are, and your dd might be very upset by their jaw dropping clangers they might come out with while you explain. It's none of their business, besides "she doesn't like being touched by strangers" and you could add, "who does?!!" is perfect.
Hope you had a lovely time after that.
It really makes me annoyed how strangers help themselves to our personal space: I'm forever getting hugged by people whom I know only a bit - co workers etc, and it drives me nuts. I must look like I like hugs.. Whereas I really don't want to hug people I work with, at all.
I don't shake hands either, as I never know where their hands have been (I have atopic dermatitis,and nickel allergies, so if they've been handling coins or keys, my skin flares up, and I broke my wrist a while back, and I find people sometimes really grip your hand to shake it and it really hurts)
I just wave my left hand in their face if they want to shake my hand now, and don't go into the medical reasons.
I think you did the right thing. I think the waitress should have kept her touchy freely needs to herself. Your DD is not a toy. She was probably shocked that she had actually touched someone, so she changed tables to avoid the situation. Maybe she's learned her lesson for the future- do not molest the customers!