Someone can be a self-injurer without having Borderline Personality Disorder (BPD). Moreover, someone can have BPD without being a self-injurer. However, it should be noted that having a history of self-injury and self-harm is one of the nine main criteria for diagnosing BPD: "Recurrent suicidal behavior, gestures, threats or self-injuring behavior such as cutting..." Of course, it is important to remember that even if one's self-injuring has gone into remission, that, by itself, is not proof of recovery from BPD if other self-sabotaging symptoms remain present.
March 1 is Self-Injury Awareness Day. Its symbol is the orange ribbon, as shown here:
A reminder to those who have a history of self-injury: you don't have to face this alone. There are people who -- even if they have not self-injured themselves -- understand what you have gone through, and will always care about you: