might have got into the inner ear to come out. repeat this process with the other ear as well. you can even make use of a blow dryer which will comfortably dry your ear. however, you must aim the dryer at the ear for about 30 seconds only. and also, the blow dryer should be kept a foot away from the ear.
after drying out the ear properly, you can apply a home remedy. create a mixture of vinegar and rubbing alcohol. apply it to the ears before and after the swim. it prevents the bacteria to get into the ears. tilt your head and pour a drop of the mixture 