I had my side of my neighbours hedge cut about 5-6 weeks ago (last week in July) - with their permission. About 5 inches of green was left. Its now turning brown. Is there anything I can do please? Will it recover or will it spread? I don't want to have killed the neighbours hedge. Thank you.

to the forum!
It's probably a little sunburn from the sudden exposure to more light. New growth should cover it fairly soon.