Whiplash is a terrible injury that is often glossed over as not being important, but many continue to suffer from whiplash long after the other injuries sustained at the time have healed.
Whiplash is basically a compression injury. The difficulty with treatment arises from attempting to maintain the necessary decompression which allows the tissues of your neck and jaws to heal. Your physiotherapist or chiropractor will be able to provide short term relief, but unless your neck and jaw joints are treated together, then long term resolution will be unlikely.
A neuromuscular dentist will be able to predictably maintain the decompression needed for resolution of your jaw joint and neck symptoms.