I'm no longer able to select my brush strokes on an image

Usually when I select the brush tool in Lightroom, I'm able to see my previous brush strokes and continue editing those. All of a sudden that is not happening. The brush tool is functioning fine other than I have no way of editing my previous strokes. The little circles (and the red overlay) that normally designate a brush stroke are no longer showing up. 

What am I missing?!