What is an adverse reaction of leaving a glycolic peel on too long?

Leaving a glycolic peel on too long can lead to burned skin, making this the correct answer. Glycolic acid is a potent alpha hydroxy acid that exfoliates the skin and promotes cell turnover. When used appropriately, it can improve skin texture and reduce signs of aging. However, extending the duration of its application beyond the recommended time can overwhelm the skin, resulting in chemical burns. This can manifest as redness, inflammation, and discomfort, indicating that skin has been damaged.

In contrast, while redness, dryness, and rashes can occur with glycolic peels under certain circumstances, they do not specifically indicate the severity of a burn caused by prolonged exposure. Redness is a common and expected reaction after a peel and can often be mild and temporary. Dryness can also result from overexposure but is less severe than a burn. A rash could develop due to irritation or an allergic reaction, but again, it does not carry the same implication of damage as a burn does. Thus, burned skin represents the most severe and concerning adverse reaction of leaving a glycolic peel on for too long.