Download and install Fallrim Tool
I have always managed to use a portable Java script environment but for this tool this didn't works.
Say you messed with the face of Valga Vinicia, her facegen data were embedded in your savegames and you ended with having her having neck seams.
What ever you do:
disable/enable (not working)
markfordelete (you are going to loose her good here)
starting with a clean Helgen Keep save didn't works as long as you are using the mod that edit her face loaded (this didn't work and I confirm that !!)
What is working?
Load your save in Fallrim
I'm not going to advise you to clean the save
instead you are going to delete a single reference from the savegame
this reference noted ACHR (by the game and this cleaning tool) correspond to 0003A198
in the case of Valga Vinicia. You will need only the 5 last digits 3A198 in Fallrim search menu.
When found just delete it and resave with a new name.
Follow the screenshots for more help.