Johnny, I really wish I could think of something more fun, but it may well be better to scrape out the top 10mm or so while it's still relatively soft.
With things like ridge tiles or wall copings, it's fairly easy to lightly "stain" new mortar to "age" it... ie to take away the newness. In your case I guess you want to keep the result bright and cheerful.
I can guarantee that you would spend far more time and money trying to blend it all in, than you would by re-doing.
I have seen where some have painted all the pointing with Masonry paint. Believe me... the result is usually awful.