Addressing a shower pan that was not sloped properly
It sounds as if you practically have all the concrete removed. It may be wise to bite the bullet and start anew. For the sake of consistency it's better to have a floor pan from one single installation.
It certainly is possible to install patched areas in concrete and have them function as expected. Shallow chisel divots can be filled and if the area is solid without cracks and hasn't been jolted-loose from the demolition the odds are good for a repair.