wow, really nice design and concept (well, not nice but you know what I mean)
maybe make the expression a little more “extreme” and tilt the head a bit. Open the mouth a bit more, squint the eyes a bit. I think for screaming like that, the top corners of the mouth would be raised higher and the cheekbones (I think thats what they’re called, the area next to the nose and under the eyes) may bulge a bit more. I think the eyes would be shut or almost shut and the head tilted back slightly. It might sell the whole in pain/anguish look a little more if that’s what you’re going for. especially the front shot seems not to show as much emotion as I think it could.