You'd need to re-show the screen with `show screen whatsit` generally - if you call the screen and then jump to a label, that ends the interaction with the screen and hides it automatically. You might also consider showing the screen on the master layer if needed so you can show sprites in front of it etc.
I see, the problem I was having with that was that when re-showing a screen, it repositioned it to it's default origin, so I was hoping for something that would just show the label's contents within the screen.
HOWEVER, I ended up using "renpy.call_in_new_context" in a function and called that function within the imagebutton and it did pretty much exactly what I wanted. I did still end up putting it all on the master layer like you said, just in case.
Thanks again, you've been a big help!