I think you should pursue it, not to get the dog put down, but to instill some responsibility into the owner.
Also, the medical bills are going to be expensive.
I was bitten about a year ago, and had to get all of the shots - rabies, tetanus, etc.
Bills added up to over $5,000.
I just let it go when I was bitten, and that was a huge mistake. I was out of town, got bitten by a dog on a freaking retractable leash. I ran by the owner on a road, she let the dog run up behind me and bite my leg. I yelled at her, she cried, I felt bad, said it was no big deal. I asked her if it had rabies, she said no. When I got home I told my doctor, he advised to go ahead with Rabies vaccination b/c apparently dog owners will lie through their teeth about those vaccinations - even though it could end up costing the bite victim their life. Way too late to go back to another state, track down random dog owner and figure it all out.
I am not sure why so many people are coming on this thread and giving advice on how to avoid being bitten. The guy was already bitten.