log in problem, please help.

so i logged out of my acc(am using iphone) and the next time it asked me how i wanna sign in and out of curiosity i chose guest. now my apple id and game center is set on my guest acc and i cant open my old team, the only way is to log in through facebook( i already set my real acc with facebook) but due to regional problem i cant do that without using vpn and i dont wanna do that, is there anyway to set my apple id and gamecenter acc to my old team? going almost crazy here, any kinda help would be appreciated.