I found an alternative to SMP.

I just tanned my head haha.

Tanning works like anything that changes the contrast between hair and skin color. The darker your skin with dark hair, the less the contrast between hair and skin color. I often recommend that men with very white skin get a tan. Dying it blonde works even better for the white guys, maybe not for darker haired men. SMP also changes the contrast between hair and skin color, see here: https://scalpmicropigmentation.com/