@kungook at least you can try a reset, but careful because you will still need to have the password etc. to get into your phone even after a reset. Check for some ways of resetting your password on here. Without that your phone is not going to work for you.
Xiaomi Mi 5 Hard Reset (you will lose all your personal files like pictures, music etc.):
Turn off your phone.
Next Press and Hold
Volume Up + Power button (or)
Home button + Volume Up + Power button (or)
Volume Down + Power button (or)
Volume Up + Volume Down + Power button
Until you will see Android reboot menu.
Then select option: “wipe data/factory reset” using Volume Down, and Power button to confirm operation.
After that choose option “yes” with Volume Down, to select and Power button to accept.
After that press Power button to enter option “reboot system now”.