if anything what will happen to him?

it can cause swimmers ear in its ear. do not put anything in your dogs ear…ever!! my vet yelled at me for trying to use a gauze to wipe my pits ears out after he jumped in the pool…simply put lint can get left behind that could do even more damage. they have ear cleansers at most pet stores or you could take him to the vet and get a cream to put in the ears that is antimicrobial and anti fungal. its in a blue tube, its called entederm ointment.it works really fast, and sooths the ears while it heals them.