A drug delivery device, in the form of an injector, may include one of a number of systems for limiting the delivery of a medical fluid or drug product in case of movement of (e.g., removal of) the injector relative to the patient as determined by a proximity sensor. The drug delivery system may in the alternative or in addition include systems for indicating the amount of medical fluid or drug product delivered (or not delivered) in case of movement of (e.g., removal of) the injector relative to the patient as determined by the proximity sensor. The injector may be, for example, an on-body injector or an hand-held autoinjector.