Will there be enemies that influence your size? Examples being making you being in a cave and enemies making you grow to the point of it being a hassle, or being in some dense forest or jungle area and a foe shrinking you down to make the area even harder to navigate than it already is.
I have some enemy in mind that could change your size (make you normal-sized), but it's a late stretch goal. Getting too tired will make you shrink back to normal person size too. There been other similar suggestion about being trapped in covered structures or being shrunk down below normal person size.