That's a hard place you're in. Do you have any close family or friends (besides your parents and boyfriend?) that you feel comfortable enough to tell? If not, I encourage you to tell your therapist. I have had to deal with this as well and know how ashamed I felt having to tell my mom/friend/therapist what I did. But sometimes telling someone and talking about what made you self-injure is helpful. Yes, it may worry them, but I would think they would rather know so they can try and help you. I know that when I try to hide it I feel anxious and like there is a giant sign over my head that says "I CUT! I CUT!" As guilty as I feel, it feels good to get it out.

Good luck