Some thinbgs you need to know:
The first time Vam encounters a .dsf file, it converts it into a .vmi file (a tiny file containing morph information) and a .vmb file(a larger file containing the morph data itself). It never opens the .dsf file again.
This decreases startup times, as on startup, Vam only needs to read the tiny .vmi files instead of the whole big morph file.
So if you deleted the .dsf file, but left the corresponding .vmi and .vmb files, you have not removed the morph.
Also note that the display name of the morph (what it's called in Vam) is stored inside the .dsf file. And inside the .vmi file Vam makes. This is independent of the moprh file name. When you created the .dsf, facegen made the display name the same as the .dsf name. If you simply changed the name of the .dsf, the display name will not change. So the name it shows up as in Vam will still be the old name.
If you just want to change a morph name, the thing to do is open the .vmi file with a text editor and change the "ID" and "display name" there. Then change the .vmi and .vmb file names to match. While you have the .vmi file open, you may also want to change the "region" field. The region is the morph category on the Vam morph dropdown list the morph will show up in.
Here's what a typical .vmi file contains:
I confess I'm not sure what the difference is between "id" and "display name", but my policy has always been that since I don't know, it's probably safest to keep them the same.
Strictly speaking, the ID name and the morph file names don't have to match, but God help anyone trying to manage their morphs if the names don't match, so the user can't tell what file any given morph is in. If you want to remove the "cleavage2" morph, and there's no file named "cleavage2"... what are you supposed to do next?
Also note that once you change the name, any looks made using the old morph will now be broken.