I think that Barron's power just... uses the parts of your mind that forget things, to hide your real memories, and make new ones. I don't think he really gets rid of the old ones, people just don't know to look for them anymore.

It's like he gives you amnesia. If you know you have amnesia, you try and remember things, and eventually maybe you do, but because he puts something else there instead, people don't try to remember them correctly.

He can't actually take away what's happened to you.