creating a perfect spherical hole in an orphan mesh (Abaqus)

Hello All,

I have an 3D orphan mesh (Abaqus)  that I obtained from the Gmsh software. I would like to insert a perfect spherical hole in that mesh.

I selected all the elements inside a sphere and deleted them but i am getting a very coarse surface, look at the figure attached

Is there a way to create a perfect spherical hole in a 3D Abaqus mesh ( I do not have the part geometry)  ?

I thought something like,  smooth the inside of the surface of the mesh deletion, but I donot know how to do that.