I mean, at this point, you might as well be a good sport about it. It was a hilarious situation that Cavill found himself in back at the end of last year when he had to sport a mustache for Mission: Impossible - Fallout but also had to return on-set of "Justice League" for reshoots.
The very idea of them digitally removing Henry Cavill's mouth brow was a running joke for many fans and, surprise surpise, a major qualm for the many more that saw "Justice League." If you look closely you can definitely see the CGI erasement, of course, one can just let go and, you know, watch the film instead of focusing on Cavill's upper lip, but it turned out to be quite the distraction for many.
Over on Reddit, the VFX artist in charge of Cavill's mustache said the WB offered Paramount the option to digitally create a CGI mustache for the Mission: Impossible film, in return for Cavill to shave the damn thing. It was obviuously a pain and very complex process to digitally remove the mustache, but Paramount didn't budge, they said Cavill keeps the lip rug:
“A mix – to some people it’s a cool little project to get stuck in to and another problem to solve, which is what a lot of VFX is about. Challenging. To me, as a fan, I was annoyed haha Paramount should’ve shaved him and stuck a fake one on for MI6. Ridiculously petty of them. We did tests on already shot footage of Superman to add a beard as well to show the MI6 team at Paramount it was loads easier, and Warner Bros offered to pay for all the beard adding shots in MI6. They said no.”
How important could the dirty Sanchez Cavill was sporting be for the plot of "Mission: Impossible 6"? We won't really know until the film is released next summer, but suffice to say it was important enough that the WB had to go through a digital removal of it and be the butt of jokes of many film fans.
The results are, quite frankly, frightening