Michael Landon had genuinely injured his foot off-set and this had to be incorporated into the story in order not to delay the tight shooting schedule.
When Laura is in the "tub" you can see she wearing some kind fabric wrapped around her chest to keep it covered.
Laura acts offended at the suggestion that she needs "toilet water" (perfume), but the word "toilet" wasn't commonly used to refer to the commode in the United States until the late 1800s. It is also established in other episodes that the Ingalls girls are not that familiar with the concept of indoor plumbing.