80% chemical peel on dark knees (Photos)

I'm so sorry that you are suffering this way My best suggestion is that you see a dermatologist ASAP to diminish as much as possible the postinflammatory hyperpigmentation that will inevitably follow the healing of these chemical burns, particularly in skin of color. The sooner you go, the better. Of course, for other readers of this answer, it should serve as a strong cautionary lesson that self-treatment, especially with strong peels, like full strength glycolic acid, or very potent TCA, as in this case, should not be used as unsupervised home treatments despite their ready availability these days through the internet. Home, self-treatment on the surface seems like a cost-effective way of dealing with certain skin problems. But, as this particular unfortunate incident demonstrates, it can often prove penny-wise and pound foolish with potential long-term or permanent pigmentary complications. Once again, I am very sorry that this has happened to you, but I strongly urge that you seek prompt intervention to minimize to whatever extent possible troublesome, long-lasting pigmentary problems and potential scarring. My very best..