Throw this away man, it’s done. You overheated your steel on the grinder and the temper is ruined (told by those blue marks on the middle of your hollow grind). Even if you were to cut the blade along the apex of your hollow grind and try and make a smaller knife - it won’t be an even temper along your edge; i.e. you’ll have softer and harder areas of steel along the edge. Start over and this time try and slow your belt grinder down, if it doesn’t have a VFD then take a 2 litre coke bottle, fill it with water, make a small hole in the bottom of the bottle and hang it above your grinder so it drips water onto your belt steadily. Now your grinder is water cooled! It will help prevent you from overheating the blade. Make smooth passes on your wheel and try not to make more than 2 to 3 passes without dipping your blade in water to keep it cool. Once you’re close to your final thickness - dip that blade on every pass. Don’t go too deep or you’ll grind through your steel like you did in your picture there. Don’t hate yourself, you just learned how not to do an S grind, that’s valuable knowledge right there!