@Marakesh hydrotherapy apparently is very useful for lymphodema which is the basis of the Encore program run by the YWCA in some states. It is a free 8 week course - 1 hour exercise/ information session on a number of topics of interest to breast cancer people eg Otis foundation for free holidays , garments suitable for those that have had mastectomy etc. , PLUS one hour hydrotherapy. I found it very worthwhile on many levels not the least was meeting others in the same boat.Not sure where you live so can’t advise if available in your location.