When I have this problem I just paint the brush along the entire panel line. Then I let it dry for about 10-15 minutes (use a hair dryer to speed it up). This leaves excessive paint around the panel lines, of course. I remove the excess with an artist's kneaded eraser, available at art supply stores, craft stores, and even stores like Wal-Mart might carry them.
This type of eraser works very will with removing excess oil paint from my models. I just form the eraser to size and shape I need and gently rub off the paint. I often form a fine point or a flat-head screw driver shape. If the paint is wet, the paint comes off with a simple touch. If it is dry, you will have to rub it a bit but it still comes off easily. This process is tedious, but less tedious than re-scribing, and much more forgiving!
Personally, I use a flat finish for this process, so test this on a scrap to make sure the eraser doesn't mar your gloss finish. It doesn't affect my flat finish.
Another option I use is colored pencils. I just sharpen to a fine point and draw into the panel line, using a straight-edge if necessary. This creates a sharp line, so it may not be your cup of tea. I try not to use a black pencil, instead I pick out a darker color of the base coat. Burnt Umber looks great on olive drab, for example. Again, I use a flat finish, so it may not work on your gloss coat.
Good luck and let us know how it turns out.
Chris