Showed evidence of penetration from that night or prior to that night?
Both. There was fresh bruising and some blood, which were described as acute (from that night) and also evidence of previous trauma, including the erosion, which was described as chronic. Many people get confused by the term "chronic" they confuse it with "chronic" as in chronic illness, meaning over a long period of time. In this case, the term chronic simply means that it happened on at least one occasion OTHER than the acute injuries from that night. This could mean that JB may have only been abused one other time (at the Dec. 23 party, perhaps?) But it could also have been evidence of repeated sexual contact. There is simply no way to tell from the evidence how many times it occurred, other than it was more than once.