not sure what you mean by dust? but if it just looks a bit hazey then keep it lubricated and itll heal great

usually it will start to flake and peel. After that it will look kind of shiny, and the skin wont quite look right yet. Its just that the skin isnt completely healed and back to normal. Usually from the shiny point its a week or two and then it should be back to normal. If you are talking about spots where the color is just missing, this could have happened from excessive scabbing and will need to be touched up by your artist.