The invention relates to an injection device for injecting dosed amounts of a liquid therapeutic agent, with a receiving device for the therapeutic agent, an applicator device for transferring the therapeutic agent to an application site, a dosing device for transferring the therapeutic agent from the receiving device to the applicator device, a trigger device for activating the dosing device, and a detection device for detecting the applied amount of the therapeutic agent. A sensor arrangement is provided which comprises at least one identification device, which identifies whether the therapeutic agent has reached the application site or a site different than the application site.