If there is a facegen in the cache, I'd guess ithe game will keep using it absent 1) a manual reload, as you discovered or 2) clearing the cache. I'd clear the whole cache and let the game force itself to relook for the photo file the next time it needs it.
Clearing the cache involves the .lg file and won't touch the master which I presume is under /data and the appropriate subfolder.
Here are some threads where I've assisted on this in the past:
https://forums.ootpdevelopments.com/...d.php?t=360691
https://forums.ootpdevelopments.com/...d.php?t=358207