In Emacs how can I go back to the last buffer I was editing in ELisp?
In Emacs you would type
Ctrl-x b to do that, so to find the Elisp function, type
Ctrl-h k followed by
Ctrl-x b and you'll get:
[...] (switch-to-buffer BUFFER-OR-NAME &optional NORECORD)
Make BUFFER-OR-NAME current and display it in selected window. BUFFER-OR-NAME may be a buffer, a string (a buffer name), or nil. Return the buffer switched to. [...]
which should do what you want ;)