Wax is supposed to break down scar tissue by providing moist , deep heat specifically to tendons. I don’t think using paraffin is a secret for it’s use in injury treatment.
Years ago I was in clinic and met a young guy who had both his feet crushed by a machine at his family’s business. His feet were very seriously injured. As I was telling him about the wax he quickly replied he had already bought a paraffin bath and was using it multiple times a day and it was making a huge difference for him.
I remember going to Italy in the Spring of 1988. We were coming back from a meet in Sestriere ( Italy). At this facility I met Mennea who was jogging around the track doing a workout. There were whirlpools and cold dunk tanks and paraffin tanks as well.
That was a long time ago now and this kind of information is not new. People are reluctant to accept easy methods of healing or treatment in favor of treatments where cost is prohibitive.