Hi ,I had breast cancer in 2020,lumpectomy  and all my Lympthnodes removed from under my right arm. This caused me to.devlop mild lymphedema in my right arm,and I was told to never have bloods taken ,or blood pressures, injections ,drips etc ..any work done in my right arm indefinitely...meaning never . Id speak to your breast care team  about it,they should be able to answer your questions if your unsure about what you have been told . Hope you get some answers soon .