Because the twrp said that installion was done so it looks like you had it installed.
Next thing you can do is the upload the update zip again, becaus there might be something wrong on your last package. Try that and proceed.
Basicly;
1. Remove your zip and download it again incase that something went wrong last time.
2. Reboot to recovery, install zip. Do not boot straight to system.
3. In recovery, press back, wipe cache and dalvik and then reboot to system. And be patient, it might take awhile
As for me i got stuck on white mi logo with update line under. I waited one hour and then i shut down and boot back and i got succeed.