Healing takes time, there is no way for your cells to instantly regenerate/reform.
Maybe try some makeup if you have access to it, a plaster maybe would do. I would ask why you would not want them to see said scratch but that would be prying too much.
If it is only short term, and has been correctly cleaned then it is okay. I am not saying to use it long term, but if you really have to, it will work for an hour or so.