I rewatched it and, yeah, I can see why you think that.
I didn't really notice a few things at first; with some more attention you see she's got her mouth twisted in a slight, perpetual sneer - one corner of her mouth is clearly higher than the other. And it is probably because, like she's saying, she has skin missing inside one of her damned CHEEKS and... can't... physically fucking relax her mouth ever again.
Which is maybe why her speech is also punctuated with frequent pauses and sharp inhales through the nose. Though the pauses could just be the steady decline in her ability to cope with and process the horrors eventuating across her bodily form in real time.
She's also wincing and trying to hide it but, again, could be equal measures dealing with the physical pain vs. trying and failing to cope.