You probably do not have any recourse, unfortunately. While it may be that a decal would have been a good idea, the fact remains that you walked through a glass door. Since glass doors, in homes, offices, and stores, are common, and many do not have decals on them, there is nothing inherently unreasonable--or negligent--about having a glass door and not having a decal on it. You, on the other hand, would probably be found to have been negligent, or careless, in walking through the door, since every day, people navigate un-decaled glass doors without incident, showing that there is nothing inherently dangerous about glass doors--i.e. you probably had a moment of inattentiveness or otherwise were not paying as much attention as you ought to have. While you deserve sympathy for you pain and costs, the fact remains that if the fast food place did nothing unusual or wrong, and you, conversely, were likely at least somewhat careless, the fast food place is not liable for your injuries or medical costs.