We all know that an increasing number of adolescents self-harm, as in scarring. Withstanding the fact that adolescence is known for the strength of its co-called "testing the limits/frontier-testing" behaviours, the issue raised here is of the specific nature of the relationship maintained between such behaviour and the adolescence process. Sey-harm is explicitly favoured there. Through the image of a lacerated body, resorting to scarring raises the following issues: of the differentiation between internal/external space (frontier); of the modalities of exchange that take place through the medium of the body and related to the barrier-excitment process; of the bearing made possible thanks to the limit and to the possible printing-representing option found on the body surface. Modalities described by D. Anzieu as set onto the skin-ego. Based on clinical projective results of adolescents who self-harm, we shall try to draw out the characteristics of this investment of the body surface, both in the weaknesses and in the elaborative resources it reveals.