Struggling with Self-Harm and Lying to My Doctor

I'm new here and I want to be able to find support and give it. right now I have been struggling with something I said to my doctor when I was fifteen years old. I was seeing my pediatrician with my mom and my doctor starts doing the usual mental health exam. he starts asking if I've ever thought about doing self harm. I said yes. then he asks if I've ever done that. I watching my mom out of the corner of my eye, said no. I flat out lied to my doctor. At that point in time I had been self harming for over six months. I was scared and didn't want to admit the truth. My mom knew about my ED was mad with me about. So when the appointment is done, we get into the car where my dad is waiting and my mom tells him about the appointment. Dad asks if I say no about the self harm. I told him I said know. dad then says, "you know how we'd feel about it, right?" I say they'd be sad when my mom says they'd be mad with me. My mom had anorexia in highschool which I didn't find out till after she found out about my ED. It confuses me because I thought my mom should be more understanding than angry with me. Granted I'm more than likely not seeing from a parents perspective. But why did my friends all have parents that understood and weren't angry with them when mine would be? I'm actually over two years clean on self harm. But I've never told anyone except my friends. I've told every adult I know I've never hurt myself. Yet I clearly have. I bear scars on my skin from my own doing. And while I'm proud of how far I've come, my question is, has anyone else done this? Has anyone else lied about something as major as this? Should I have said something that day and risked my parents anger?