I stole a chest of 3500 dollars from my boyfriends parents house chest a year ago and spent it on botox and other aesthetic treatments. I still feel guilty

When I was 17 I got into a serious relationship with my boyfriend who is 22. He's a good guy. He's very good looking, hot like Gigi Hadids ex. He's introduced me to his parents and they're the most happy people ever. They just smile all the time AND THEY'RE RICH TRUST ME. They have a personal floor for each of their three kids (his other sister has graduated and left home) and a first floor that's common. I've been there a few times and they've always treated me so nice. We have a huge dining room with a massive dining table and a cozy living room. I've been there a few times now AND IM THE MOST INNOCENT GIRL EVER but I've always been wondering what's in the chest in the attic. THEY ALWAYS KEPT THE KEY WITH THEM. Everytime I was there I would wonder if it's jewels, cash or important things like inheritance or something. TRUST ME IT WAS VERY TEMPTING. My ex boyfriend used to live on the floor I was on when I first met him. He still has his room there. But I think a year before I met him the whole house had a renovation. So now AND I DONT KNOW WHY but the attic has a small entrance that is only accessible AND ONLY ACCESSIBLE from my boyfriends room (the one that's on the bottom floor) It looks like a locker. BUT they dont have a key for it so they can't get to it AND ALL THEY CAN DO IS USE A DIAMOND CUTTER TO CUT THROUGH IT. ONE TIME WHEN THEY HAD GONE OUT I WAS IN THE HOUSE ALONE (I was waiting for my boyfriend to come back home from work and I think his parents had gone to visit a relative) and I just ran to his room and found a big diamond cutter. I used it to cut and then went into the attic and opened the chest and found thousands of dollars. I grabbed a bunch of it and went to the first floor and hid it in my bag. They came home later and didnt notice a thing. Please note that trusting me AND THEM with this chest is a BIG responsibility and I feel so evil I did this. I used it to get full face botox and lip fillers and other aesthetic treatments with some of it. By the time I was done with the treatments I had only a thousand left. THAT I HAD TO SPEND ON A DRESS AND SHOES. BUT I TELL YOU I STILL FEEL TERRIBLE. They still dont know and they still dont know about the DIAMOND CUTTER. I still feel so bad. What can I do to let go of this guilt