The scar should not be red or hot. I would also take her temperature and make sure that is in the normal range of 101.5 to 102.5. The incision should not be oozing any fluids. The do look better with time after they flatten out and lighten, but trust your instincts.
Here's a good link to car sickness - it covers everything from behavior modification to dramamine dosage and other natural anti-nausea and calming remedies.
http://lowchensaustralia.com/health/carsick.htm