Final answer:
A mask should generally be applied in a thin layer during a microdermabrasion treatment, using a spatula, brush, or disposable sponge for even distribution.
Step-by-step explanation:
When applying a mask to the skin during a microdermabrasion treatment, it should typically be applied in a thin layer. However, the specific requirements can vary based on the type of mask being used and the individual's skin type. A spatula, brush, or disposable sponge can be used to apply the mask, each offering a different level of control and hygiene. For precise application and even distribution, a spatula or brush is often preferred, while a disposable sponge can be more suitable for a hygienic, single-use application. Regardless of the application method, it's important to follow the product's instructions and to ensure that the mask is applied evenly and gently after the microdermabrasion procedure is completed.