In the context of health intervention research conducted jointly by patients, hematologists and education researchers, we present the self-care pathway of Paul, a patient with hemophilia. In a biographical interview, Paul described his active prophylaxis process and more specifically how he moves from a perception that something is wrong with his body to the decision to self-care. Throughout this article, we will study the links between sub-clinical warning signs and what makes an event, visual perceptions and the different stages of learning. To do so, we rely on two conceptual anchors: the phenomenology of perception and sensitive life and the anthropology of education and training.