Hi,
You may be able to replace the part but you will destroy the waterproof integrity of the camera in the process.
Here’s a link to the ifixit [guide|44307] guide.
Whilst it is not a repair guide it shows how access to the camera’s internal components can be achieved and what tools are required.
At Step.13 in the guide the module with the LCD screen has been removed from the camera.
Here’s a link to a [https://www.ebay.com/itm/Original-LCD-Display-Screen-Module-Assembly-For-Gopro-Hero-Session-4-Camera-Part/163746280371?hash=item262009f3b3:g:mZ0AAOSw8EhdDKxz|supplier] of the part.
It is shown only to let you know the cost of the part and what it looks like.
There may be other suppliers online that suit you better. Just search on places such a Ebay etc for ''GoPro Hero 4 Session parts''