broken cylinder head bolt please help

Well I’m mad. it’s the bolt on the front left of the cylinder it’s one of the long ones. I was taking the cover off to change my valve seals. the bolt was super tight I new it was gonna happen. I dropped some we 40 in it and let it sit for a couple hours but to no avail. how bad is this? I mean is it gonna hurt the engine? how can I fix. or repair?