Found myself having to install a splint on an old maton top. (no Kim, the crack did stay glued but split along a new grain line 2 days later

The splint went well but I'm wondering how to blend the new wood in.
I have limited resources here at the moment.
The owner doesn't care how the guitar looks, but I do.
Thanks
(Oh, and Kim, the other cracks have blended in really well after a rub with hot water & left to dry - cheers mate!)