A Temporary Setback

He only heard a faint bump when he should have heard something a lot louder. Merlin's fears from the previous day came true as he sat there in bed trying to process it.

The ringing had gone, but he still couldn't hear anything.

OR

Merlin gets injured in a fight and is rendered temporarily deaf. He doesn't want Arthur to find out, but he does anyway. Angst and hurt/comfort ahead.