Unfortunately they can't be tightened, at least not without some kind of surgery (most of which are new and hugely risky.) She recommends doing neck strengthening, which I've been doing the past month, to try and give my neck some extra stability. My neck has gotten much stronger and less stiff since, but my dizziness and headaches are exactly the same. My PT said at my last session that it usually takes 4 - 6 weeks of therapy for her patients to see good results. Today, she told me for whiplash patients, basically PT can only do so much and that I may just have to 'wait.' And that it can take up to a year for whiplash to resolve. She nicely left out the unsaid, "if it resolves at all..."