What happens if you leave hair color in too long?

Leaving hair color in for too long can lead to several adverse effects, including hair damage, dryness, and breakage. The color may become overly intense or result in an unintended shade, as the dye can penetrate the hair shaft excessively. Additionally, prolonged exposure can cause scalp irritation or allergic reactions. It's essential to follow the recommended processing time on the product instructions for optimal results.