Sometimes getting the item damp and putting it into the dryer for a short time could puff it back up again. Good luck.

This reply is for DawnM, who asked how we can know if a batting has scrim. I just purchased Hobbs Heirloom cotton batting from Connecting Threads (on sale, yea!) and they said in their description that it has scrim and it says "with scrim binder" right on the bag that the batt comes in.

What I DIDN'T know was that scrim will melt under high heat, so this "thread" has prevented me from making a serious mistake when I use this batting.

I am someones MIL and my thoughts would be " How beautiful that my DIL would take the time, energy, patience and LOVE involved and required to make something so very special.
I would leave it as it is and say nothing to the MIL about the ironing.
My guess is......she wont even notice!
She will more ingrossed in the fact that the quilt is so beautiful and that you took the time to make something 'personal' for her.
Shop products mean nothing to me.
Just as I enjoy getting a handmade greetings card from my children , rather than a shop one.
Crazy but true.

What a wonderful mother-in-law you are and how lucky your daughter-in-law and your son are. God bless!