What is that on my photo?

You can toggle through the info overlays by two-finger tapping on the image. It will cycle through three states:  "no overlay," "info overlay," and "histogram overlay."

It's likely you touched the screen with two fingers to get into this mode in the first place. 

Hi there,

We are sorry about the experience with Lightroom mobile.

Would you mind sharing the model number of the phone you are using and the operating system version you are using on it?

You can close the preset panel and go back to the image, then tap the 3 dot icon on the top right and toggle the option to Show Histogram off to remove the histogram.

Regards,

Nikunj

It's the histogram, but it appears that your display is all messed up.