That's the reason I asked if you have also one word for "to finish showering".
We have no one word even for "showering". Verb "душится" is already taken by two another different words.
However this can be changed to "мыться" ("wash himself") and "домыться" sounds like what you want "to finish wash herself".

But be aware of post just above. "Домыться" is "to make last (finishing) steps of process of washing yourself".