Hi there, I hope this message finds you well. So when, I try and rotate the sculpt for the mouth, to open it, rotates my entire model, instead of the selected elements. Also when placing my cursor it disappears into the mesh. I am not sure why
when placing my cursor it disappears into the mesh
Make sure that you have Surface Project enabled (you can do that when in your Cursor Tool):
and for the rotation, look at the size of the influence of your Proportional Editing (adjust by scrolling the mouse wheel), might just be too big.