16F My brother found out. I don’t know what to do

So In November my brother (23) had a talk with me asking if I had ever self harmed because he has seen some scars on my arms. The scars that he saw weren’t in perfect lines and could possibly look like an accident so I just lied through my teeth the whole time and blamed it on the dog. But today I was in the car with him and he noticed the scars on my leg and said “what’s that” and at that point I just didn’t say anything because It was so obvious I couldn’t lie. He said that he’s heartbroken that I would do that to myself. He also said that he’s going to tell my grandpa about it and I’m honestly so scared and I have no idea how he’s going to react. My family loves me but they’re very religious and I’m scared that they’ll start forcing me to go to church again because of this. He asked me how long ago I did it and I said I haven’t done it for a whole year (which is another lie). I’ve been doing it since i was 11 and now I’m going to be 17 in april. I’ve been clean for only a couple weeks. He said he won’t see me differently or judge me but I just don’t believe him. Now all I can think of is the fact that my brother knows I cut myself and now everyone probably will know too eventually. I’m so ashamed and disgusting. I’ve lied so much and now he probably will never trust me again. I’m genuinely a monster. All I do is hurt my family. I didn’t tell anyone about this because I don’t want to hurt anyone more than I already do, but here I am anyway. He also made me show my arms and of course I had scars there too.All because my shorts were a bit too short in the car and my scars were noticeable. I’m genuinely such an idiot for that. This wouldn’t be happening if I just wore pants like usual. The worst part is that I have literally nobody to talk to about this. I have no friends. This was the worst day ever and I don’t want to wake up tomorrow