Bottom touch pad not working

@yash64085 that sounds like a failed touch screen. In the case of this phone the touch screen is part of the display assembly. Replacing that will more likely restore the function. Of course, it is always possible that this is a connection issue or even a logic board issue. Get a new display and while you replace it check the other things as well.

Since there is not a specific guide for that on iFixit yet, use something like this video Replacement display assemblies are readily available at many online stores.

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has a device with the same issues as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!