Redirect causing issues

I hope someone can help. I am currently working on a website but my client has requested that the domain be temporarily redirected to his facebook page as he has inadvertently published the web address in an advertising campaign! I have done this for him through his control panel / DNS but I hadnt realised that in doing so I would no longer have access to the wordpress site to continue work – how can I get round this problem?

Cheers

Steven