As they say in the quilt world, finished is better than perfect. Just take it as an experience to learn from.

I say "leave it alone"... it's for a 6 yr old... it is gonna get dragged to grandma's... to sleepovers... you name it! It will be loved and adored, and used to keep him warm! Relax... no one else will know, and don't point it out! You did an amazing job!!!