Never use dry ice. To ice a sore Achilles tendon, place a handful of ice cubes in a sealable plastic bag, place a protective layer like a facecloth between the ice and your Achilles, then hold the bag in place with an elastic bandage. Some runners treat a persistent ache by applying heat, whether using a heating pad or jumping into a hot tub. This is the worst thing you can do. Heat will increase swelling and inflammation.
Some runners mask problems by taking aspirin.
Aspirin's analgesic properties will lessen inflammation and swelling, but they also mask pain associated with overuse. ASAP after a workout. It's important to differentiate between an ache and a pain. An ache is a low-level discomfort associated with exercising. A pain is a sharp or intense discomfort that may suggest injury.