A medical injector (200) includes a medicament container (210) including a main lumen (214) and a reduced-diameter protrusion (220), a needle assembly (230) coupled to the protrusion (220), and a flow control member (250). The medicament container (210) is configured to contain a medicament, such as, for example, a dermal filler. The flow control member (250) is disposed within the protrusion (220) of the medicament container (210), and includes a flow control lumen (254) configured to control a pressure or a flow of the medicament. Thus, the flow control member (250) reduces decoupling forces applied to the needle assembly (230) by the flow of medicament. Alternatively, the flow control member (250) may move from a first position allowing flow from the main lumen (214) to the needle assembly (230) to a second position blocking flow from the medicament container (210) when the needle assembly (230) decouples from the protrusion (220).
