A medical device and methods for filling tissue are disclosed. The device has a first configuration wherein the device can pass through a small catheter or needle placed in the tissue to be filled and a second configuration in which the device is expanded within the tissue to be filled. The exterior profile of the expanded device may be customized along its length, to achieve a desired cosmetic or therapeutic result. In one embodiment, the device comprises an outer sleeve for containing filler and a valve on the sleeve for retaining the filler therein. The device is adapted to be placed through a needle in the skin to reduce facial wrinkles or augment facial features such as the lips.