can't unlock the phone

I can connect to the phone and see the screen, the phone is PIN locked, but as soon as I swipe to enter the unlock code, the pin code screen is shown as blank and enetering the right code also does nothing.
My phone is hauwei mate 10 and the screen is broken, so this is the only way to get in, but without being able to enter the actual pin code, all I can see is the lock screen