It takes time for salt to migrate from a brined surface to the center of the cheese. So, inadequate brine can contribute to problems down the road, but swelling this early is most likely a contamination problem originating in your raw milk. With early gas production, it is most likely a coliform - not good. That's one of the signs that you look for with bad milk. There are many possible points along the way that would result in this, but the primary cause is sanitation at the farm. How quickly was the milk cooled? To what temp? And how did you take care of the milk in transit and at home? You should NEVER let raw milk warm up unless you intentionally want the native bacteria to grow.
All milk has at least tiny populations of contaminants, so establishing the starter bacteria quickly will help out compete the "bad bugs". When using raw milk I add starter very early to the cold milk so they get a good head start. They don't really start multiplying and eating lactose until things warm up, but neither do contaminants. When things do reach ripening temperatures, there will be billions of starter compared to relatively few contaminants. As the starter produces lactic acid from lactose and the pH drops, the environment becomes less favorable for contaminants.
If you haven't already, I would pitch that cheese. Please do not "taste test" it. Not worth the risk.
