 [ Symptoms ] where can i find out what quantity of omega 3 fatty acids is present in a particular food it is not listed in labels [ Disease ] i can not offer you a definitive answer based solely on your brief description i would need to see and exam this child but one possibility would be impetigo    a staph or skin strep infection there can certainly be many other causes ten year olds like to swing on bars during recess and often get blisters if they pick at those blisters on a dirty hand it can become secondarily infected and this infection can spread to the mouth quite easily