Always perform a patch test on a small area of your skin before applying a new mask to your entire face to ensure you don't have an adverse reaction. Additionally, avoid applying masks too close to your eyes, nostrils, or mouth, and be careful when using ingredients like essential oils, as they can cause irritation if used in excessive amounts. If you experience any itching, redness, or discomfort while using a mask, rinse it off immediately and discontinue use.