Applying ice to a pimple can help reduce inflammation, swelling, and redness. It can also temporarily numb the area, providing relief from any pain or discomfort associated with the pimple. Additionally, the cold temperature can constrict blood vessels, which may help decrease the size of the pimple. It is important to use a clean cloth or wrap the ice in a cloth to avoid direct contact with the skin to prevent ice burns or frostbite.