I had a power strip that I attached to my plaster wall with double sided tape, which I now really regret, because when I went to take it off, it took a big chunk of the wall with it, revealing the cement beneath. I tried to shore it up with spackle, but the wall is still uneven. Worse still, this is a rental, and I want to try and fix it before my lease is up so I don't have the land lord charge me a lot of money for something I could fix myself. Are there any ideas to fix this wall? Thanks for your help.