In a D&D 5e game that I'm in, I play an arcane trickster rogue. We recently added a new player to the session, specifically a bard. In character, we try to one up each other all the time. It just seems to be how our characters interact.
So, one morning the bard was performing in an inn, and I decided to cast invisible mage hand to mess with the strings on the lyre he was playing. Our DM informed me that I took 5 psychic damage (after he rolled for damage). When I questioned it, I was told that the bard's instrument deals psychic damage when played by someone not attuned. I can't find anything about that when I tried researching, so I conclude that this lyre is a special kind of bard instrument. I accept the DM's ruling on the matter and that won't change.
However, out of character, I'm really curious if that was the correct ruling? Here's my argument: if I use mage hand to set off a magical fireball trap from a distance, and my mage hand get's hit, I do not take damage (unless that's being played incorrectly). So in my mind, the psychic damage from the instrument should have been directed at the mage hand, and not me. My logic may well be way outside RAW at this point, but it seems to me that the instrument couldn't have known it was me messing with it. On the other hand perhaps it could because it's obviously a magical instrument.
So, when an arcane trickster tries using mage hand to play an instrument that deals psychic damage to anyone not attuned who plays it, should the trickster take damage? Also, is this a special kind of instrument, or does this apply to all bard instruments and I just missed that feature in my research?
Clarification: I'm interested in the interaction of mage hand with this instrument, knowing that my rogue as the caster of mage hand was not attuned to the instrument. I accept that if my rogue had walked up to the instrument and tried to play it, he would take psychic damage. I didn't roll a saving throw.