Was I at fault for this dog attack?

it was your dad's fault for allowing a giant dog to be possessive of a couch to the point of biting ... it was in no way your fault ... nor did the dog snap ... it was allowed to behave that way by your father ... don't worry, everyone has sucky childhood memories of when our parents screwed up ... it was not your fault, just a father clueless about dogs, their behaviour and training ... sadly you had to pay for his ignorance by being bit in the face ...