i don't have a recent back up
It is bad form to do a OS upgrade without a fresh backup before the upgrade, for the reason you have had the bad luck to encounter.
Does no "recent" mean you do not have any backup at all while using 10.12.2? If you have a older 10.12.2 backup then you will be in much better shape to revert.
Here are the basic steps to revert to 10.12.2,
without any 10.12.2 backup:
1. Backup your current internal drive with 10.12.3 installed to a external drive. I recommend a clone.
2. Obtain the
full 10.12.2 installer. 10.12.2 is no longer available for download from Apple, so you will have a problem if you do not already have it.
3. Make a bootable USB thumb drive installer with 10.12.2.
4. Boot to the bootable USB thumb drive installer with 10.12.2, erase your internal drive, and install 10.12.2.
5. You’ll have to manually copy back over any files you saved from 10.12.3. I do not think the Migration Assistant app will work, but you could try it. Setup user accounts, set preferences, and install apps (skip this step if Migration Assistant works).
Here are the basic steps to revert to 10.12.2,
with a older 10.12.2 Time Machine backup:
1. Backup your current internal drive with 10.12.3 installed to a external drive. I recommend a clone.
2. Connect the Time Machine disk with 10.12.2 on it.
3. Boot to Recovery. At the “macOS Utilities” screen, choose “Restore From Time Machine Backup” and then click Continue (the restore process will erase your internal drive).
4. Copy interim files. Once the downgrade is complete and you’re back to 10.12.2, you’ll have to manually copy back over any of the new interim files you saved from 10.12.3.