100% and more if possible agree with Wolfstraum.
That is why I started the socializing thread because we see so many young dog's put into situations that will affect them adversely for a very long time.
OR ill prepare them for a well socialized life .
What you did in YOUR attempts to socialize the dog did not help your dog one speck.
Actually OTHER DOGS socialize your dog .
Your dog was impulsive , went into the personal space without ritualized meeting and greeting , and paid for it.
You have to go to the Vet and get anti biotics. Looks like your dog got a pretty good penetration in the gum/jaw line . You don't want any possibility of infection or abscess which will infect behind they eyes or brain .
Sometimes having a wild zoo of activity at a dog park is a better atmosphere than entering a dog park with only one dog in it (from the dog's perspective). The dog already there could perceive the area as his private domain, his territory. The dog entering this situation may be apprehensive and then to have your dog rush him , friendly or not, was too much , too fast, too close , and your dog got a piece of canine discipline from a canine.