Hydration well with electrolytes is needed more than people realize. Marching in the hot sun and/or other activity can really drain fluid from one's body. Daniel (and others) in the marching situation should stay hydrated with fluids. It may be likely that the "marching" is also preying upon Daniel's mind in a negative way due to his lip/embrochure complications and pain. He he may need to work through it as necessary to keep up. If all else fails, seeing a medical doctor is usually a good thing pursue to be on the safe side.