I knew a guy who got hair plugs when he was in his late twenties. He was concerned about his receding hairline, so he had the front of his head filled with hairs from the back of his head. I didn't notice at the time, I suppose it just looked like he wasn't losing his hair.
Later in life, he became a little more self confident and wanted to stop the process of getting hairplugs. Unfortunately, his natural hairline kept receding and his original plugs were holding fast. What remained was a sort of sand-bar of hair in the front of his head.
As you traveled up his forehead you would pass his eyebrows, his forehead, his hair plugs, then a bald zone and then his hairline. It was a mess. Eventually, he just did what he should have done originally, he started shaving his head.
If you want your pumpkin carving to have hair you can use grass plugs. You might be trying to created the flat-top of the Terminator. This pumpkin is supposed to be the terminator. I am not really buying the Terminator, but I do like the grass for hair.