Sadly i still dont understand :/
Don't know if you still need this, being months after your post and all, but you will need to find the downloaded mod in your NMM mods folder. I think mine was something like 'Nexus Mod Manager\Fallout4\Mods\CBBE HeadRear Fix-12839-V1.7z'.
If you copy that file to somewhere else and then extract it, when you open it up you will see an .esp file, probably called CBBE.esp. That .esp name is the same one that the base CBBE mod uses, so when you install the mod through NMM, it will overwrite the CBBE plugin.
All you need to do is rename that .esp file to something else (like 'CBBE HeadRear Fix.esp'). Then just change the name of the whole main folder (which was CBBE HeadRear Fix-12839-V1, or something like that) to something like 'CBBE HeadRear Fix - Modified' and then use 7zip (or whatever you use) to compress it again. So now you should have a new compressed file called 'CBBE HeadRear Fix - Modified.7z'. Import this manually to NMM as a new mod using the Import from File button.
When you install this mod, follow the usual instructions:
1. Don't let it overwrite 'femalebody_d.dds', 'femalebody_n.dds' or 'femalebody_s.dds'
2. Copy your textures for the above files from your 'Data\Textures\actors\character\basehumanfemale' folder into the 'Data\Textures\actors\character\CBBE' folder overwriting any existing files with the same names.
3. Check you NMM plugins and make sure that the new 'CBBE HeadRear Fix.esp' is appearing and his higher in the load order than the 'CBBE.esp'
Should be good to go. This worked for me for raiders/femalebodydiry as well as my player character, however I haven't tested for female ghouls yet.
Hope that helps, either you or someone else looking for the same thing. Have a great day!