Considering skull reshaping to round the back of my head. Is this procedure safe and what should I be aware of?

Hi The back of my head is flat and I have wanted to something about it for so long. I found that it’s possible to do a skull reshaping in USA by two ways, one way which am considering to do is putting bone cement under the skin of the back of the head and make it more rounder. The procedure sounds extreme and it doesn’t get done all over the world I would like to know if it’s safe and what I should be aware of. Since I am traveling a long way for this.