I Spilled My Brother's Precious Paint Set...

So there I was, hanging out in my brother's room without his permission. He has this paint set he loves so much, every color and shade is perfect for him when he's doing art stuff. Anyways, I was just looking around his desk and decided to take the lid off one of the paint pots... And then I knocked over the entire thing onto his notebook where he had all these amazing drawings that he worked on forever. Now they're completely ruined with this weird brownish-black color spread all over them. I've been sitting here trying not to freak out for like an hour now. It was an accident, but it's still so wrong of me to go through his stuff and I'm scared if he finds out he'll hate me forever or something. We're only a year apart in age but sometimes he feels so much older than me because of all the cool things he likes that are way too mature for my taste. I tried cleaning it up as best as I could, but there's no hiding this one... He always knows when I've been in his room since there’s a certain smell that only comes out from under his bed. Now every time he walks by and sees me, I can see the disappointment on his face before it even turns to anger. I've never felt so guilty in my life. What if this ruins our friendship forever? What should I do...