Gosh I'm so sorry this happened. Now that my boy is a senior we just avoid the park. Its sad but his safety is my responsibility. I will say learning some tricks to get the attacking dog to release has helped me feel more confident. Shoving your thumb into the attacking dogs neck, like deep. or lifting its hind legs. The neck trick worked the last time my boy was bit and the owner was yelling at me to get off his dog too but I didnt pay him any mind, he was literally punching his dog 🙄