If you were able to turn it back on, it should be fine. I think that hardware these days are generally designed with some shielding in mind (i.e. the motherboard is electrically disconnected from the case at its standoff mounting holes). But it probably isn't best to open the panels while operating, especially on carpet because of the static you might generate when you move around and when the bottom part of the panel rubs the carpet when you slid it off. Next time, you might accidentally touch a circuit and fry things.