First of all, I’m glad that your parents are going to take you to a therapist to address your cutting. Your cutting is a warning sign that something in your emotional life needs to be addressed. While there is confidentiality between client and therapist, there are limits to that confidentiality. Therapists are required ethically and by law to intervene when a client is threatening serious harm to self. Since cutting can range from minor surface scratches to life threatening wounds, and I don’t know how serious your self-injurious behavior is, I am not able to fully answer your question. Your question can be best answered by your specific therapist when you meet with him or her. At your first session, I suggest that you ask your therapist how he or she will handle your disclosure of self-injury. Because you are a minor, it is likely that your parents will be involved in some way in your treatment. Many therapists will require family therapy when working with minors because family dynamics often play a part in a child’s distress, and because parents play an important role in the healing process.
My biggest concern regarding your question isn’t whether or not your therapist will tell your parents, but why you don’t want your parents to know the full extent of your self-injury. Is it because you are embarrassed of what they will think? Is it because you don’t want to upset them? Is it because they will be angry with you? Is it because they will overreact? I hope you will address this important question with your therapist.
The fact that your parents are taking you to therapy to get help tells me that they are concerned about you, that they care about you, and that they acknowledge that you are in pain and need professional help. Consider that they may be able to help and support you through this difficult time as you sort through your emotions and resolve the pain underlying your self-harming behavior. You are 14 and it’s their job to make sure you are safe.
Take good care of yourself, and let your parents take good care of you, too.