when i had my iPhone 5, i dropped it in ketchup and got it in the speaker grill and charging port. i tried to get as much out as possible and was banging the bottom of the phone to do so. somewhere in the process i damaged the speaker and brought it to the apple store because i was still in under warranty. they replaced the speaker for me but it wasn't still 100% as it seemed the speaker was aimed upwards into the phone. the same guy who changed to the speaker decided to just give me a refurb.
i say make an appointment and give it a try.