She initially asked for her medical costs to be covered. McDonalds declined, so she went to court.
Full thickness burns are not a trivial injury. She was at risk of death. Treatment is painful and takes a long time. She would have been left with scarring and perhaps loss of function - because a fast food chain didn't care about customer safety.
Do you have access to a thermometer? Try measuring the temperature of a cup of coffee that you make at home tree minutes after you've made it.