Before saying anything I will share my test image :
As you can see the forehead having a half-circle, and between the circle and the rest of the face in the boundary there is a sharp transition which is quite visible.
If I want to make it smooth, then how should I do it.
I have tried with median blurring inpainting etc. But none giving good results.
Following are some of the result that I got :
So what else can be used to solve this problem?