ZBrushCentral

Help! I accidentally deleted Sub Div level 1

Working on my Head bust on sub div level 3 of 6.

I went to save my file and somehow I had managed to delete sub div level 1 .
My current sub Div level 1 is in fact sub Div level 2.

Now I have an early save (about 4 hours earlier) which has the right sub div level 1.

The shape has not changed that much as I have been working on higher levels adding surface details.

How can I re-introduce the original sub div level 1 into my current save?
I need to retain all my sub div levels

I have tried importing the original sub div 1 to the current scene and it messes up.
Please can anyone help.

It’s ok.Solved it.Used the Reconstruct Sub div option.
Phew!!!

works the majority of the time but never if you have triangles.