PS4 Controller model CUH-ZCT1. Released in November 2013 by Sony Computer Entertainment, this six-axis, 3.7 V lithium ion battery controller is uncomplicated to repair. (NOTE: Teardown guide is NOT for this model)
You can try and disassemble your controller using the guide below and try and render the touch pad functional again. If that doesn’t work you may be better off getting a new touch pad, they are very inexpensive to buy.