The present invention generally provides improved medical devices, systems, and methods. Some embodiments of the present invention apply cooling with at least one small, tissue-penetrating probe, the probe often comprising a needle having a size suitable for inserting through an exposed surface of the skin of a patient without leaving a visible scar. The cooling may remodel one or more target tissue so as to effect a desired change in a composition of the target tissue and/or a change in its behavior. Exemplary embodiments make use of replaceable needle probes supported by a probe body handle, with small needle probes often being replaced during treatment of a single patient. Careful control over the control of cryogenic cooling fluid into a needle probe can allow the length of the active cooling to be controlled through depletion of liquid from an evaporating cryogenic cooling flow.
