I Have Black Hairy Tongue Since Being At The Dentist

I have black hairy tongue since being at the dentist yesterday. I have been rinsing with peroxide for the past week to help my irritated gums before getting 2 crowns yesterday. My concern is that it is moving to my teeth on both upper and lower right side of my mouth(where drilled for crowns). Will this go away and my teeth come back to their normal color?