Well... I do think it is true, at least based on my own experience, that self-harm can become addictive. (I've read that this is the case as well.) And so from that perspective, if one does become addicted to it, I don't know if one does ever leave it behind entirely. One simply learns how not go back to it day-by-day, very much like people who have been addicted to alcohol or drugs learn to not start using again... one day at a time.
It's so unfortunate your social worker feels it is her place to give you a load of judgmental attitude. I know you wrote you refuse to address your cutting in real life. But it might be worthwhile to consider talking about this with a competent mental health therapist.
Cutting isn't the worst thing in the world. But it can pose a health hazard if you're not really careful. (You probably don't need me to tell you that.)

It seems as though some people find themselves cutting deeper over time too which increases the risk of serious injury. Plus, from what you wrote, it sounds as though you have some conflicted feelings about what you're doing. So perhaps it is adding some additional anxiety & stress to what you perhaps have anyway. Living day-to-day can be stressful enough without adding more on top of it.
Anyway... you mentioned you had not cut for almost half a year prior to your relapse. Hopefully you can get back to building on that success & this recent relapse will be just a temporary setback. We all have those from time-to-time.