hit the wrong key and turned 3D view into render, also
How to close windows in 2.79 - 2.8?
Go to the corner with the three diagonal dashes of the window you want to keep and drag towards the window you want to disappear.
Good sculpt so far. Good proportions and anatomy.
Alternatively, if what you really want to do is fullscreen your 3d view:
While hovering over the 3d view with your mouse, hit CTRL+up-arrow. (CTRL = CMD on a a Mac, I think.)
That will make that window fullscreen so you can work on just the model but still have the outliner, etc., available in the background. To reset your window from fullscreen to its original divided position, just use CTRL+down-arrow.