Accidentally ran find / -type f -print0 | xargs -0 chmod 0644

I have run this command find / -type f -print0 | xargs -0 chmod 0644 accidentally instead of find /home/user/public_html -type f -print0 | xargs -0 chmod 0644 My server is not working, though I got to know something wrong happening, I have cancelled the task. Now I can access whm and the terminal but rests websites are getting 500 error. Any way to revert the file permission? Fast response is kind appreciated.