Hello:
I believe that you should use C-c C-k . This will compile and load a lisp file on my pc (I'm not sure if you use the same slime version). In my pc, C-c C-c only compiles the file, but doesn't load It.
I should add, that when I close Emacs, restart it, get into the LTK environment and load fgs, then the changes show up.
Well, surely, if you do (load "fgs" ), lisp searches the compiled file and loads that. Then the changes show up.
I hope to be helpful