Writing down all you can remember about the situation you were in when you decided to self harm is an important step in learning self care, imo. If you find you can't put things together, then perhaps your T would be able to.

Self harm is a coping mechanism (albeit a less than good one ) it's a symptom of something else....

if you can find out when you self harm, why you decide to self harm at that time and not others... then you can begin to work on what is causing you to feel so bad that you want to do this.

Maybe you really don't see any connnection... maybe a check off sheet with all the things to try and note would help you more? Did you smell a particular fragrance or odor? What were the songs on the stereo? Who was around you? Who should have been around you? What interactions did you have when you decided you "needed" to self harm? Was it a phone call? An argument? A feeling of lack of control with something? A feeling or thought of inadequacy?

Of course there are many more things you might be able to check. IMO, trying to stop self harm in and of itself does little good if the reasons are still in your life.