Someone who's recovered has been cured or has otherwise returned to a normal state. A recovered cancer patient was sick but is now well.
Recovered patients get released from the hospital, and recovered athletes are allowed to return to the playing field or court after healing from an injury. When lost or stolen objects are recovered, they've been found. And when memories are recovered, they're remembered after being forgotten for a long time. Recovered comes from an Old French source, recovrer, "come back or get again."