We are not 100% on the details, but my mother returned home from work to find a half mauled wild rabbit in the backyard, Chico with a small graze on his lip and Diego with a puncture wound in his chest. We don't really have any idea on how this all happened, who ate the rabbit, who attacked who first, but we are under the impression that somehow Diego and Chico had an altercation on who would eat the rabbit and Diego ended up with Chico's canine teeth in his chest. This has caused quite a large, deep puncture in his chest. Luckily, there is only a few other scratches on both dogs, and no flesh was torn, so it seems that it was a quick fight, with Chico winning.
The majority of the swelling went down over the next couple of days, however what was left was a hard golf ball sized lump under the bite. This was slightly squishy, but mainly was just a hard mass that could have been described as tumour like. I contacted the vet to ask about this to find out if this was normal, or something I should worry about. She said this was a fairly common occurrence, and it could disappear on its own, but if it didn't, it would need to be surgically removed. Since Diego was still on antibiotics she suggested we wait until he had gone through the full dose of this before seeing him again. The puncture itself at this stage, had started to heal up and scab over.
Thankfully, on Saturday a week and a half after the bite (his dose of antibiotics finished on Sunday) his lump had gone down significantly. It now no longer stuck out of his chest, and was not visible from afar. You could still feel the lump if you touched the area, but it was so much less imposing. As of today, the lump is hardly there. There is an area around the original wound that still feels tough underneath but the vet suggested that this would just be scarring from the bite itself.
The scab has come off the puncture wound and the wound has healed wonderfully. There is a bit of hair loss where that wound was, as well as around it where other teeth must have grazed past but no major scarring as of yet. We were incredibly lucky that everything healed up so straight forward, and that the fight itself hadn't been more intense.
I was very worried during this whole experience, especially with the hard lump as there wasn't much information on the web about a lump forming after a dog bite. I wanted to share our experiences in case this helps at least one other person if they find themselves in a similar situation. Thankfully, Diego was playful and his normal self during this whole experience and didn't seem overly upset about it. Him and Chico are still best mates, and play together at every available opportunity. Chico's lip graze now looks as though it was a point where Diego made contact with his teeth, and that has also healed amazingly well and he had no need to visit a vet for it.