The Beautiful Waterfalls, Lake, River, and Ocean
Perhaps we are being overly pessimistic, but wouldn’t it be better to spend your time helping yourself recover through various therapies rather than spending three weeks in the water hoping for a miracle?
Having said that, there is some evidence to suggest “cold water immersion” or as we refer to it, the Atlantic Ocean, for recovery of DOMS (delayed onset muscle soreness) after high intensity exercise, but just not for enhanced recovery after a muscular injury.
Therefore, it is improbable that walking in a chilly sea or a magical river after suffering a muscle tear can damage you, but it is also unlikely that it will have any beneficial effects beyond placebo. Increase your strength if you want to get better.