Bathroom tile replacement
I need help replacing a heavy tile on the bathroom wall. The tile tile came loose and behind it was thick white thinset. I attempted to remove the old thinset and in the process removed large chunks of what appeared to be concrete over the drywall. There is also a glossy white plaster looking material over the concrete like substance. What can I use to patch that concrete like material and can it be applied over the areas that still have the glossy white plaster material.