Agree, I think I'd consider this tank a loss. If you wanted to attempt to salvage it, see if you can find a bulkhead with a larger diameter hole than all of that and re-drill it. Like drilling a cavity, you'll have to remove all the damage. I don't know how big that whole mess is, so you might not be able to find something big enough.
If it's a large/expensive tank, you could look into replacing that side. But it'll almost certainly be cheaper and easier to fix the problem now rather than wait and see if you have a leak you'll forever be dealing with, or worse, a catastrophic failure at some point.