Installing ceiling fan

Paint should not damage the functionality of the ground. Flip your breaker off and clean it up. Flip breaker back on and test it. You can get a electrical receptacle tester at hardware store for about $7, very useful device that will help you ID any issues with any of your power outlets. Alternately you can use a multitester to test ground, just search for videos or articles for how to. Flip breaker back off, install your fan, and you should be set.