Oh how perfectly sweet. It's beautiful! You did a wonderful job!
Just think, your son doesn't know what the mistakes are, he just knows it's soft and warm. As he grows those small imperfections won't be mistakes to him, but loving characteristics of his favourite blanket.
Every stitch, even a wrong one is a stitch that passed through your fingers. Each one was knit with love. That's all your son will see.
(though, I don't see any mistakes myself. I think it looks just perfect!)