Never install a balancer without the proper installation tool
You stripped the front portion of the threads on the crank. Run a thread tap to clean it up and re-install balancer with the proper tool, Disount auto should have them, they are cheap. When the balancer is seated properly on the crank you can use the bolt to snug it up.
I feel your pain, been there done that but only once, won't repeat that mistake again.
PS, a balancer installation tool is not a big hammer