Your son is young, he won't notice as I am sure no one that you show it to is going to notice. I had to look at this closely to see what you were talking about. If it bothers you, rip it out. Otherwise, just leave it alone. I have made some mistakes and they were on my mind, until I posted to this group and they put me at ease. I left my quilt alone and since I don't dwell on it, I don't see it, nor does the family member I gave it too you.
As I learned here... If you can't notice it from galloping by on a horse, then no one else will notice it