It could be, but it's difficult to tell from the pictures. These traces are not necessarily severed in my opinion. Mostly it looks like the solder mask was scraped off. But the copper is very much intact in most places. I do have questions about this area (noted below). Because it looks like there may be a crack there, or just shadows from solder mask (the green stuff) Which could be a problem.
[image|3516665]
The copper is what carries the electrical signal, so exposed copper isn't usually a problem. The scratch would have to go deep enough to cut through the copper. Or crack it. So the electrical flow would be broken. It's also possible components were knocked off? Can you also add an image of the overall area?
I am more likely to think, if you're not getting power at all and the issue is the same now as it was before the scratch, the issue isn't the SD card anyway. Most computerized devices will power on with bad storage, they just won't boot or they'll crash. If the issue occurred after being connected to a PC that could be any number of things, but it could be a different unrelated issue with the board.