You can also try mixing 1/2 cup hydrogen peroxide with 1/4 cup Dawn dishwashing soap. Put this mixture into a spray bottle. Sprinkle baking soda on the marks and then spray the mixture on that. I've had a lot of success with this combination (though I've never tried it on Frixion pen marks).
Hugs and good luck!

One of the things that helps get out Permanent marker is taking a dry erase marker over it, then use the eraser over it. My daughter is a teacher and swears by it.

Watching to see if any of these suggestions work. So sorry for you and your quilt top!

I am so sorry for you. I can't even imagine. Alcohol worked for me once when I had a pen in a uniform pocket in the washing machine. Also, I always have success on stains with Blue Dawn dish detergent. I mix with a little water and use an old toothbrush, rub it on the stain, and then throw the piece in a washing machine with lots of cold water (not in a high efficiency) and let it soak overnight. It gets all the stains out. I haven't used bleach in years. Maybe it will work for you.

I am SO sorry. Hopefully one of the above suggestions will work for you.

Hmmmm... I know that works on SmartBoards & white boards. Never heard of it being recommended for fabric. If it does work, it doesn't work all the time. One of my second graders tried that on his white uniform shirt one day when I had a sub for the morning. It definitely made the stain way worse (we were able to eventually get it out, but with way more effort than if he'd just left the mark alone). I would test this method on a piece of scrap fabric first.

I would love to see this quilt! It sounds amazing.

I've had good luck removing even Sharpie black marker from granddaughter's white dress using a spray liquid called Insta Lift. It took three tries, but the mark is gone completely. I've used it on other clothing as well with no bad effects on the color or fabric. It's made in the USA.

ordered this on amazon. thanks Jane

I had a client (90s) press her small quilt top with the Blue Be Gone still on. I tried soaking it overnight with a product called "Linen Wash" by LeBlanc (made in the USA) and the Blue Be gone was gone the next day. I have never tried these pens before but with using an iron for the marks to disappear, that just makes the hair on the back of my next stand up. Is there any type of applique that can hid the areas?? Hugs coming your way!