Kind of a funky way to have a scratch! If this were my carboy, here is what I would do. Gently, but thoroughly, wash the area with a soapy dishrag or sponge with a temperature of 70 to 75 degrees to prevent temperature shock. Rinse completely and dry. Allow to air dry. Now take another look. If it is a visible scratch, gravity rack the wine into another carboy. Certainly, DO NOT attach a carboy handle to lift.
Along that thought, the only reason I use a handle is to aid in washing or carrying an EMPTY carboy. Carry or move a full carboy using a Brew Hauler or like device with handles. Better yet, do a "net" search for "carboy covers", something that zips up tight to the neck, has two grab handles at the top, another grab handle at the bottom, and a slip resistant bottom. Now you can safely lift and move the full carboy, the carboy is somewhat protected from harmful contacts, and the ultraviolet rays are kept out during aging.
