Leave it. It really is hard to notice and I can sympathise but is will beloved either way and I like the responses that say the monkeys are facing up towards the receiver. My 10 year old boy made a quit once with me and when we quilted it we noticed one block up the wrong way. It was of zebras and was a close together print so wasn't too noticeable and we just decided the zebras wanted to be seen the right way up. He is now 15 and still loves that quilt and what he did.