I'm not smart. so i have a serious question. if i tell a professor i am on exchange will he still fail me?

if i fail any subject, my year long exchange program will end and I will be deported. studying in australia has been hard for me. i come from a uni ranked 68th in the states.... but the uni i go to in oz is ranked 15th in the world or so. so its a big step up. change from quarter to semester system was big too. so if i write exhange student on my exam or email the prof my circumstance, do you think he will still fail me? has anyone on exchange failed classes and provide insight?