It looks like it might be necrotic, but YES, put the zip tie back.
If there is indeed some dead tissue where the bark looks black in the pic, the cambium should regrow over the next season or two anyway. It could be a long wait, but there is little choice, IMHO, as this would still be the fastest way to recover.
This year I will use homemade graft pins... I was thinking in a similar nail as you see here https://store.bonsaitonight.com/products/grafting-nails using silicone from those hot silicones guns (they don't ship to Chile).
But will probably use the same tree as I think it stuck on the other side.