just did an update and now cannot get in without password and i cannot remember password

I just did an update on my Iphone 5 it is asking for my ID and password. I know the ID but cannot remember the password. It states I need it because my phone has the Find MY Phone app on it. Which must have been added at the last update. I don't use that App and do not need it. Can someone tell me how I can unlock my phone? Please.