Spoilers below for anyone who hasn't yet watched The Walking Dead's Season 8 winter finale.
Nobody likes it when a big and enjoyable work gig has to come to an end, especially when that gig is seen by millions of people on a weekly basis. Being killed off of a show like The Walking Dead, while certainly a bummer all around, does at least offer the former stars and actors the freedom to not worry about sticking to a very specific look for their characters, many of which are meant to emulate the comic book source material. For Chandler Riggs in particular, it meant he could cut Carl's signature long locks, and could also go public with it.
For one, I don't think we've seen this much of Chandler Riggs' face since Season 1 Carl's hair was still too short to even stick out from underneath the hat that Rick gave him. While almost everyone else in Team Family has maintained a pretty steady appearance, the Grimes men have seen a constant evolution in the hair department, though Carl's hair mostly just grew out, as opposed to the various changes that Rick has gone through. Now that Carl's days are numbered, though, with all of his future scenes already filmed, Riggs is likely grateful that he is finally free from adhering to his Walking Dead-specific appearance in the future. Especially if his vision got wonky from wearing an eyepatch on the set all that time.
Of course, having to keep up a particular appearance isn't exactly the worst thing in the world, and I doubt anyone would readily drop out of The Walking Dead in order to change it. (Steven Ogg wants to shave his instantly iconic mustache, but probably not enough to make a self-imposed exit.) Of course, when Chandler Riggs first cut his hair recently, that was one of the clues that fans used to predict that Carl would be getting killed off in the show's near future; and sure enough, that future was set in stone when Carl revealed he'd been previously bitten by a walker. But now that the midseason finale has been out for a full week, Riggs is able to finally go full-on public with his new shag-lite appearance.
As previously stated, The Walking Dead's comic books generally feature characters with pretty locked-down appearances, though changes do happen. And even though the comics are all in black and white, Michael Cudlitz's Abraham developed an immediately recognizable look with a head full of fire-red hair. The actor has retained the mustache and facial hair after leaving the show, but he has reverted back to a more natural color scheme.
Steven Yeun, whose Glenn got his head caved in during the same episode that Abraham's head got caved in, didn't necessarily have any specific physical characteristics that tied him to the comic book character, as it was his baseball cap that brought the biggest connection. But there was apparently something that Yeun loved about performing with blood covering his face, since he recently promoted one of his post-Walking Dead projects with the below image.
It'll be interesting to see where Chandler Riggs' career goes next, since The Walking Dead largely detracts its biggest stars from joining any other longterm mainstream projects. Will the actor continue in the horror genre, or will he branch out into broad comedies and fantastical musicals? Either way it goes, he probably won't need to revisit Carl's look.