According to the convention operations manual (which I can't locate a link for right now) I believe an overseer is to immediately contact WT legal dept. Someone from the operations committee should keep following up with a local elder, who should keep checking on the injured as to injuries, etc. (probably to make sure the claims aren't exxagerated, especially in claims of serious injury)
The injured is encouraged to use any available medical insurance they may have. If the injured does not have insurance or it is exhausted they can forward copies of the bills to the elder who can give it to the operations committee who can give it WT legal and they can review for possible payment of actual expenses.
I'm sure no compensation would be provided for lost income, pain and suffering, etc. If you did pursue this I'm sure you'd be looked down on. Any compensation would probably limited to actual medical expenses.