This question has been answered several times and a little time spent looking at old posts can shed a lot of light on new problems.

The Dye you are talking about is Crocein Scarlet when sold by Kodak and Neucocein from Agfa/Ansco. Is applied on the base side if the film. Retouching with pencil/graphite was seldom done on the emulsion side. I explained this on the last go round of negative retouching. Retouching fluid is more like thinned varnish and is used for giving tooth to the base side of the film.

The only proven way to hide a deep base side scratch is to use a strong mix of Crocein Scarlet or black india ink (The real stuff) carefully make a line on the base side of the film covering the scratch I use 0000 to 00000 sable
brushes. I have even used the small Sharpies. The ink on the base side will be rendered slightly out of focus when the image is focused using the grain on the easel. Why is it slightly out of focus when you focus using the grain? Because of the thickness of the acetate film base. If you retouch on the emulsion side it should be perfectly obvious that when you focus on the grain you are also focusing on your pencil work! Thus emphasizing your repair work. Print the best print you can, then retouch the soft edged white mark on your print.

Another way though time consuming is to cut a piece of matte acetate to the same size as the negative. Tape the acetate matt side up and the shinney side in contact with the negative base. Do the retouch of the scratch on the matte acetate rather than directly on the film base this gives an extra thickness to further help soften the edges of the scratch when printed. You may do several layers of the acetate if you need to. The place the neg in the enlarger, stop down one or two stops, we don't need depth of field here we need to diffuse the retouching. Wide open is even better provided you are focusing on the negative grain.

Charlie................................