I think you may have a valid claim against the bar for, at the very least, payment of your medical expenses. As a patron of the bar you are a "business invitee." This means that the bar owes you a high duty of care. If there was anything that they could have done to prevent you from being injured (i.e. not overserve the customer, anticipate the fight and ask the people to leave, or anything else) and they failed to take steps to protect you, they will be responsible for your damages. A scar on...