Can I place expander in forehead through hairline to raise hairline and have a hair transplant to cover the scar afterwards?

I have a small 4 cm forehead. I want to raise it about 2 cm. I want the expander to be placed through my hairline instead of behind it because I would just get a hair transplant after to cover the scar. Is this possible or will the stretched skin of the forehead make it to wear the skin will become too thin to graft hairs into the scar? Also, I don’t want my eyebrows raised.