There is a reason I love this quote and it has nothing to do with its original context, although I do love Nietzsche.
It is that there are times when you look into a deep, painful subject, it is like it turns back on you. Like you cannot think about it without getting immersed within it.
You cannot conceptually think about pain, without thinking about Your pain. And being in pain, thinking about it, makes it worse.
This is what I think about chronic pain. The abyss. You stare into it because you need to cope with it, grasp it, understand it in order to live with it. Yet it seems to curl back into you... and you get sucked into this spiral of 'what does this pain mean?' or 'what if this pain never ends?'. The abyss will gaze back into you.
It is inevitable because we live at the very edge of the abyss. We stare into it on a daily basis. And at times, we get consumed by the intensity of that all-consuming pain. All never-ending aspect of it all.