Can bite splint change jaw alignment permanently? wore for 3 days and had ear fullness both ears for week with no reflex in right ear. stop wearing?

Unfortunately: These are devices that require long term use. Just like braces, where even after you've used them, often you need to use a retainer to "keep" the results you've obtained. These are usually considered propriceptive devices, meaning that they train the "body" to sense where it should be. Problem is when you stop using the device for a long time, things often go back to where they once were!

See your dentist: The dentist who made the appliance for you should evaluate your bite again to make sure that there is no interference when you move your jaw into the various excursions. You ear issue may be totally unrelated.