What you describe is a different problem to the one that the resetter tries to fix. Not been able to add manually a face is not something prevented but a corrupted DB and Gallery crashing is definitively not something that I've seen before because of that problem.

I'm sorry, but for me this sounds much more like a tracker problem, as it is also in tracker where the face tags are added.

In any case, what you can try is:

1. Delete de DB.
2. Open Gallery and let it automatically recognize a face. Check that it works.
3. Immediately, "Protect" the DB.

From that point on, the Facerecognition DB should work correctly. If you keep suffering that problem I would suggest to check tracker.

You can always reset tracker DB but, unfortunately, doing so you would lose your contacts.

A solution would be to export your contacts, reset tracker's DB and import them again.

Hope this helps.