EYE ROLLING AND FEVER !!

My 21 month old son has been having moments where he starts rolling his eyes sometimes he also rocks back and forth when it happens. Usually before it happens he starts deep breathing it all started one night when he had a fever of 103 after getting his 18 month shots. Hes now 21 months and its still going on. We are on our way back from california and he has got a fever of 103 to 104 Im so nervous hes going to have a seizure in the car. We could stop at the hospital right now ( our home is still 4-5 hours away ) but we would most likely have to stay in a hotel over night + the cost of his treatment if he gets any) anyways, it will be REALLY expensive. I have looked it up on google and it goes away in some children. Has this happened to anyone else?? Should I just say screw the price lets go to the hospital now or wait till we get home? He seems really sick and my gut is telling me to stop