Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
To convert your page back into the English language as a setting, not as a translation:
Log into your Facebook account.
Click on this link:
and choose English as your language.
That should complete the process of changing the Facebook page, your page, into English, not just translated. Let me know whether or not it has succeeded, please. Thanks!