See Which Areas of My Photo Are Clipping?

In the Basic panel, click on the little triangle in the top-right corner of the histogram to see areas that are clipping the highlights, or the little triangle in the top-left corner for shadow areas that have turned solid black. Now, any areas that are clipping in the highlights will appear in red (as seen above), and you can drag the Highlights slider to the left to reduce, or hopefully remove, that clipping. If you turned on the shadows clipping warning, those areas will appear in blue, and you can fix them by dragging the Shadows slider to the right.