When we moved in a few years ago there where a lot of 4 inch holes in the wall and my brother in law used a mesh and then some spackle and just used a putty knife and didn't sand the splackle down at all over a few of these holes. I want to smooth them out so that they blend into the rest of the wall. Can I just sand them down and then prime? Do I have to sand them down and then do a skim coat with joint compound instead? I've never used joint compound before.

Hi, We had a hole in wall in out garage wall due to someone not stopping the car in time and hit the wall and the fender made about an18x8 indentation. My 2 sons decided they wanted to go to store, get the patches and fix it themselves. So they went to Home Depot and as usual there was hardly no one in the store to help. I have the same issue when I go there and you'd think they were in bankruptcy or whatever.I understand they are a do-it-yourself store but recall they used to have buttons in the aisle which would make an announcement for someone to help. So any way they bought 3 size multi-pack of HDX wall repair patch and Alex Plus spackling, and used 2-8x8 patches next to each other. They they applied the spackle and kind of enjoyed playing with the applicator but I told them to read the instructions. I also told them I would try to get some advice here for them. So I an curious how should they proceed-should they use sandpaper around the edges or is it too late & they should just paint? Thanks for your input..