The encounter with the adolescent narcissistic-identitary pathologies unescapably involves the encounter with the experience of a difficult separation. The establishment of a boundary between internal and external, Self and Other, is the result of a complex process, which has its roots in the quality of the encounter with the object. Examining the clinical history of an adolescent girl, the paper explores the relationship between separation and self-cutting in the transference and countertransference relationship. Initially the patient's body and actions were the only manner to communicate those experiences that could not be conveyed by words and represented: the “skin for two” of the original psychosomatic envelop needed to be wounded, cut, broken concretely. Nevertheless gradually, in the encounter with the therapist, the young patient was able to construct a tenuous possibility of differentiation and began to get access to the idea of a difference and therefore to the first outline of a representation of absence.