What term describes a black and blue mark under the skin, commonly seen after inserting a follicle?

The term that best describes a black and blue mark under the skin, particularly after a procedure like inserting a needle for electrolysis, is ecchymosis. This term refers specifically to the discoloration that occurs when blood leaks from the tiny blood vessels into the surrounding tissue, commonly resulting in a bruise, which is characterized by a change in skin color due to the pooling of blood.

While bruising is a more general term that encompasses any type of skin discoloration resulting from blood vessel rupture, ecchymosis is a specific medical term that describes the same phenomenon but with a focus on larger areas of bleeding beneath the skin.

Thus, both bruising and ecchymosis accurately describe the condition of having a black and blue mark due to localized bleeding, making the option that includes both terms the most comprehensive answer. It's important to note that the term hematoma refers to a more significant localized swelling filled with blood that occurs when blood collects outside of blood vessels. In the context of this question, hematoma is not the most applicable term for the situation described.