Poggles happened to be in a pose that reminded me of a photo from his first day home. I put the photos side by side and this is what I found.
He's frowning a bit so his eyes are not a good comparison, but his nose is lighter... more liver coloured now (consistent with "chocolate" coloured hedgehogs), and he lost most of his dark mask. It's more pink now.
Do you have pictures of your pets from when they were a baby compared to now?