Dude....I feel for you. I've made plenty of mistakes over the years, so I know how you must feel, but don't sweat it. Maybe there's hope. What kind of damage did you find? If the piston didn't crack, the damage may be limited to the cylinder head. If so, it's possible it can be repaired. If a valve seat didn't get hammered it might be easier than you think. Don't make a bad situation worse. Assess the damage and proceed accordingly. Keep us posted.