Tone curve missing background Histogram Overlay

I updated Lightroom today to version 9. I go to edit a black and white negative, and the curve information is gone! It's just a gray mess with no information. I figure I'm doing something wrong, but I don't know what, so any help is appreciated. I'm looking for the graph (?) where I could adjust the white and black points in the curve--there would be a bunch of lines that look like a mountain. Sorry for the low-tech explanation. Thanks!