Hairstyle Afro LV4 already out in game now here some screenshot
Credit : Command Knight, Hanma Baki, BOHBONO5, Nobuo3622 Blog
Afro LV 1 = Got it from NPC dancer and missbomb
Afro LV2 = wear Afro LV1 after 10 duel you will get it
Afro LV3 = wear Afro LV2 after 20 duel you will get it
Afro LV4 = wear Afro LV3 after 150-200 duel you will get it.
*I don’t know how much exactly duel you need to get Afro LV4 but it seem like you will get it after 150-200 duel while you wear Afro LV3.