What should I do if I have a pit on my forehead?

Want to remove the forehead pits, first to know what is the reason for the formation of this pit, and then use the appropriate method to solve the following situations: 1, no pits before sleeping, after waking up on the forehead pits, consider the forehead for a long time by something pressed, so that the local blood circulation is not good, do not care about it generally after a few hours this pit can disappear. 2, forehead acne due to serious inflammatory infection or The first thing you need to do is to get a good idea of what you are getting into. The degree of surgery to repair the depressed parts flat.