Although the hair can rub off with time, it is not removable as it is glued to the silicone skin of the doll. If you remove the pubic hair patch, there will always be “scarring” on the skin.
Some premium brands like, DS or Sino Doll, come with pubic hair sewn into the skin of the doll (i.e. hair implants), which cannot be removed without damaging the doll.