is it wrong to think this?

My friend went up to me and told me that if I ever saw him with his jacket sleeves rolled down, it would have meant that he's been cutting. I don't know why he told me that, but I assume he wanted me to talk to him to why he did that. Later today I saw his jacket sleeves rolled down so I was worried and quickly walked up to him asking if he was okay, and he rolled up his sleeves and went: I was just testing you. and he smiled.
I didn't know how to feel, I was shocked, I felt like what he did was just attention seeking? I used to cut so I felt like doing this was wrong. Am I wrong for thinking he was attention seeking?