Soaking a BP dries out their skin, and can lead to a bad shed. you should only soak a BP if the snake has already had a bad shed and you need to get the pieces off.
That said a bad shed was probably unavoidable since your BP has mites. Stress can also lead to a bad shed, and mites will certainly stress a BP out.
Can you give us more details on what you are doing to treat the mites?