[@Dark Cloud] Here's the thing, Collin's mental/physical alteration whiteout means he can't see illusions if they target his body. It has to be indirectly cast on (and physically overlay/alter) the surroundings, and the way that was described in her post (the perception narrowing bit) makes it seem like he literally wouldn't see anything but her smiling creepily.
It's always on too. He has no control over it (for better or worse).