I intended to warn the therapist before showing him, but when it came to it I was afraid to. So I didn't. And when he said "What the heck happened to your back?" (well, not exactly that, it gains something in translation) I pretended I'd forgotten all about it, saying "Oh I'd forgotten about that. I sorta did it myself". He asked if my head had been messed up again (it doesn't sound so impolite/accusing/crazy in my own language, it really was rather sensitive) and I said "yes". That was that.

Thanks for your help. =)