Final answer:
Mallory must obtain a doctor's permission before performing microdermabrasion on a client taking blood thinners due to the risk of increased bruising and bleeding.
Step-by-step explanation:
Before performing a microdermabrasion treatment on a client taking blood thinners, such as aspirin, Mallory should require doctor's permission. Blood thinners can interfere with platelet function, increasing the risk of bruising and bleeding. Because microdermabrasion is an exfoliating treatment that affects the skin's surface, it can lead to increased bleeding and possible complications for clients on blood-thinning medications. As aspirin inhibits the production of thromboxane A2, a substance that helps platelets clump and clot, it is crucial to ensure that the procedure is safe for the client by consulting with a medical professional.