Hearing test

My baby just went for her 4 months old checkup and did her hearing test. The doc said her left ear present but her right side absent. Should i be worried? Also, i feel worried because i clean my baby ears with cotton bud and scared that i might have harm my bay ears and may have potentially be the reason why. Doc said she was distracted and will check again at 6 months. But im worried. Is it common for this? #askmommies