Could I have food poisoning from a mouthful of undercooked chicken?
A larger amount of food will cause more food poisoning, but food poisoning is extremely rare and won’t come from undercooked meals like you described, especially in the amount you ate. Also, food poisoning usually takes about 24 hours to be felt if it is true food poisoning. If raw or undercooked meals caused food poisoning then there would be no sushi with raw fish and things like that.