This remedy might actually surprise you.
An aunt of mine taught me this simple method when I was a kid and it works every time I get water in my ear after a shower.
What I do is...I scoop a little bit of water in my hand, then pour it into the ear that is blocked, while tilting my head, making sure that the water goes in. After a few seconds, I tilt my head the other way to pour the water out.
Sort of like..."fighting water with water"
The water dislodges the air bubble trapped inside the ear and , hey presto, you can hear well again!
Jokes aside...this works.
The last thing you would want to do is to poke your ear with some cotton bud.
If you are really concerned, by all means, get it seen to by a pro.
But my water method has worked for me fine.