Smoother finish if skimmed coat is not finished properly

There are two options here you can go crazy on sanding it down and see how it turns out but chances are you won't be satisfied as there will be a lot of filling to do, not only that there will be a lot of dust and mess . Even no It's a cheaper option my advice would probably to get it re skimmed by the professional lot less time consuming and effort. You can't beat plastering done properly.hope this helps. Noah's plastering