lactose does not build up in your system but the severity of symptoms can be more severe or lasting depending on how much and other foods you ate. if you are having gi discomfort acidic foods may exacerbate your symptoms. for info see lactose intolerance -- topic overview
lactose intolerance. does lactose build up in your system so as to have issues over a series of several hours/meals? and do acidic foods exacerbate symptoms?