A tissue expander (400, 500, 600) having an integrated drain comprising: a shell (102, 502, 602) having an injection port opening and one or more drainage holes (108, 508, 608) formed in said shell; an injection port (404, 504, 604) disposed in said injection port opening; said injection port including a needle guard having a needle guard base and a needle guard rim that extends upwardly from said needle guard base; one or more inflation ports formed in said needle guard rim that are in fluid communication with an interior region of said shell; at least one drainage port formed in said needle guard rim that is in fluid communication with said one or more drainage holes formed in said shell; a moveable barrier membrane overlying a top surface of said needle guard base and being surrounded by said needle guard rim, wherein said moveable barrier membrane is moveable between a first position for closing said at least one drainage port and opening said one or more inflation ports and a second position for opening said at least one drainage port and closing said one or more inflation ports; the tissue expander further comprising: a magnet coupled with said moveable barrier membrane; a compressible spring coupled with said magnet and configured to urge the moveable barrier membrane into the first position, wherein said compressible spring is compressible for storing energy as said moveable barrier membrane moves from the first position to the second position, wherein the magnet is configured to be repelled by a second magnet, to compress the spring and move the moveable barrier membrane into the second position. a shell (102, 502, 602) having an injection port opening and one or more drainage holes (108, 508, 608) formed in said shell; an injection port (404, 504, 604) disposed in said injection port opening; said injection port including a needle guard having a needle guard base and a needle guard rim that extends upwardly from said needle guard base; one or more inflation ports formed in said needle guard rim that are in fluid communication with an interior region of said shell; at least one drainage port formed in said needle guard rim that is in fluid communication with said one or more drainage holes formed in said shell; a moveable barrier membrane overlying a top surface of said needle guard base and being surrounded by said needle guard rim, wherein said moveable barrier membrane is moveable between a first position for closing said at least one drainage port and opening said one or more inflation ports and a second position for opening said at least one drainage port and closing said one or more inflation ports; the tissue expander further comprising: a magnet coupled with said moveable barrier membrane; a compressible spring coupled with said magnet and configured to urge the moveable barrier membrane into the first position, wherein said compressible spring is compressible for storing energy as said moveable barrier membrane moves from the first position to the second position, wherein the magnet is configured to be repelled by a second magnet, to compress the spring and move the moveable barrier membrane into the second position. a magnet coupled with said moveable barrier membrane; a compressible spring coupled with said magnet and configured to urge the moveable barrier membrane into the first position, wherein said compressible spring is compressible for storing energy as said moveable barrier membrane moves from the first position to the second position, wherein the magnet is configured to be repelled by a second magnet, to compress the spring and move the moveable barrier membrane into the second position.