Damaged my cog while taking it off. Is there any possibility of repairing it?
Top preference would be a replacement. These cogs are not expensive.
A second idea - It looks symmetrical, so I'd suggest using a small file to blend any burrs or daggy bits that might catch the chain, and then just flip it over so the "miche" branding is on the opposite side.
That way the wear will be on the back of the curve, and you can get some more life out of it.
If this is on a fixed gear bike where you do skid braking, I'd just replace it.