A clinical case in an adolescent unit of a hospital demonstrates that scarifications serve two consecutive psychic movements. The first one, related to a cruel masochism, seeks to release a tension that cannot be elaborated and that originates in a real trauma that occurred during childhood. The second movement allows for the actualisation of the trauma through the realisation of perverse scenarios (exhibitionistic in particular) in the transference movements in the unit. Paradoxically, this use of the act-symptom in a perverse context allows to restart the processes of symbolisation and of subjectivation when faced with the risks of manifest psychic disorganisations.