These look like some good questions.  Hope there are some replies. Just want to say that I had 28 nodes taken during surgery.  Afterwards, It should be part of the process to learn how to brush (maybe some classes as a part of the program)  I didn't have a problem until about 5-6 months after surgery.  I think had  I been brushing from the begining I might not have had a problem. JMO I too have wondered about a hot tub or just a nice warm bath soak.  I seemed that my problem might have started after a restful soak in a warm bath.

Linda