New year, new lymph nodes - swimming?

It's not very likely to happen. I've had lymphoedema now for nearly six years and even when I once got cellulitis (beware of manicures!) and could not wear my sleeve for a week, my arm didn't do anything alarming. It's wise to wear your sleeve as instructed, but not wearing it occasionally, particularly when the weather or environment is fairly cool, is unlikely to undo your good work. The exercise in the pool is beneficial all by itself. Happy swimming.