I attempted a screen repair

The iPhone 7 is not a difficult phone to open if you do it properly. First off I hope you removed the two Pentalobe screws at the bottom of the phone. When applying heat with a heat gun make sure to keep some distance as those things can get very hot! The phone should just be a bit hotter then it’s comfortable to hold. Start by heating at the bottom edge where the home button is and use a suction cup to get a pick under the screen and cut through the adhesive.

Follow the screen replacement guide carefully to do this properly. You only seem to have damaged the screen even further, but should still be replaceable.

PS: Try to be well rested and calm, as you’ll easily damage components beyond repair if you’re frustrated.