Covering a Mistake

I had this really adorable scrap of fabric, but I had a rectangle cut out of it. I really wanted to use it for my sister's changing pad bag. I thought I could sew a rectangle into it, but it was not working out. This is after several attempts and a lot of unpicking.

So, I cut out some circles from some t-shirt vinyl so it would look like a button. I have been thinking about adding string through the small blue holes so it looks like the button is sewn on. Thoughts?