Hello
Mask the areas you don’t want to change. Masking will work with Sculptris Pro.
Yeah I didn’t try I wanted to find a workaround of hiding arms and legs and continue dynamic subdivision sculpting so I downloaded blender 2.8 to try in it and import back in Zbrush to continue but the obj import doesn’t work atm I was with 2.79 when I saw your reply.
So I decided to try with mask, it’s doable but not as hiding, I continue like this because sculptris pro is just awesome and blender 2.79 just crashed.
I also tryed by dynamesh to continue my sculpt while arms and legs are hidden but it fulfill the space between arms and chest so I canceled.