No matter how long the shower, how much he scrubbed, Sam didn't, couldn't, feel clean. He could feel Lucifer touching him, doing unspeakable things to him. The nights were the worst, since Sam had nothing to occupy his mind. He woke up screaming every night and shrank from Dean's comforting hands. Every human touch just seemed to escalate the sensations.
Eloise was able to snuggle with him and her warmth and the thrum of her contented purrs sometimes calmed him. Sometimes the flashbacks were just too strong and even she could just be a presence. On those nights Sam, Dean, and Bobby would drink and play cards or just sit and watch a movie. Sam knew he was safe at Bobby's; he just couldn't convince his body.
Sam's therapist prescribed more medication and increased therapy to three times a week. Sam turned to his knives, the razor blades no longer enough. The blood helped, a bit. He went too deep, sometimes, and Dean had to stitch him up. Trying to do that without openly noticing the scars running all over his brother was one of the hardest things Dean ever had to do.
Art therapy actually seemed to help. Sam could never bring himself to draw his nightmares, but collages got the point across pretty well. They also helped him process some of the guilt he felt both for being a burden on his family and for existing in the first place. Mandalas let him think through everything without having to explain any of it. He took up sculpting with clay simply to keep his hands busy. Dean couldn't even bring himself to tease Sam for the knitting, though he was pretty sure everyone they'd ever met would get a scarf that Christmas.
Sam, to his own amazement, found himself laughing when Eloise stole his yarn. He spent an entire night designing a kitten-proof yarn bowl. He researched paints which were safe for cats and taught her to paint with her paws while he used his fingers. Their products were existential at best and muddy messes at worst, but Dean and Bobby hung them on the fridge as "Eloise's first artwork". Truth be told, they were proud of Sam's progress. He finally had a way to release some of the pressure safely. Sometimes the collages were all death and blood and pills, but Sam was expressing himself and his family knew what he was thinking.