Someone else mentioned bio-oil and that has worked really well for me. I have hundreds of scars on my arms and the ones from further in the past, when I stopped self-harming for a while, really faded. They only show up when I'm sunbathing or really REALLY hot, obviously for the same reasons - I'm really pale, so the rest of my skin goes red and my scars stay white. But even then, they are barely noticeable. I started again, so gave up with trying to lessen the newer scars. I just didn't see the point.

It's been ten years since I first hurt myself and although I still do it now and again and I'm definitely not proud of my scars, I'd either have to have skin grafts or stay in long sleeves for the rest of my life, so I try my best not to care and most of the time that works.

I hope you find what you need to either be comfortable with or lessen/cover up your scars.

I used to when I was a teenager, or I would get so angry I would rip out my hair. I stopped doing it though. I have scars on my arms from it, but luckily I work in a factory now where I am always cutting myself and everyone knows that so people just think all the scars on my arms are from work.
I think my mom suspected it when I was a teenager because I always had the scars but I always managed to make up some lie about why I had them there. No one except my sister once questioned it. It was because the lie I had made up seemed so far fetched.
But I don't do it anymore, I get urges and then I will count to ten or something and then i will be ok.