What product should never be applied to broken skin?

Hair color or chemical treatments should never be applied to broken skin due to the potential for irritation and adverse reactions. These products often contain strong chemicals, such as ammonia and peroxide, which can cause burns, allergic reactions, or exacerbate any existing injuries on the skin. When skin is broken, the natural protective barrier is compromised, making it more susceptible to irritation and allowing substances to penetrate deeper into the tissues, potentially leading to infections or severe inflammatory responses.

In contrast, shampoos, moisturizers, and styling gels are generally formulated to be safe for application on intact skin and hair. While they might cause some minor irritation if applied to very sensitive skin, they are not as harsh as hair color or chemical treatments. Thus, in the context of a barbering practice, it is crucial to avoid applying any harsh chemical products on broken skin to ensure the safety and health of the client.