In that case your phone must get disassembled but that needs a skilled repairman.
The next steps are as the followings:
1. Disconnect the ribbon cable of the touch panel from the motherboard.
2. Boot up the phone with disconnected TP
3. Force to power off the phone by holding the power button for about 10 seconds.
4. Reconnect the TP to the mainboard and power on your phone again.