Baptized candles have a tendency to display either current or to-be behaviors of their subjects. Skull candles, which are used for the purpose of magically controlling a person's thoughts, seem to "weep" with a certain frequency. Some of this is just due to the shape of the candle -- the eyes being one of the shallowest points, therefore make it likely that the liquid wax will pour out of that spot -- and one must be cautious with candle readings to comprehend what is normal burn behavior for a style of candle.
Nonetheless, a weeping skull candle can indicate many things. I might suggest he subject is upset or will become upset by thing thing you're requesting, or it might indicate that he or she is already unhappy. If you get a sobby little skull candle as part of your work, consider whether your demands on the person might be too emotionally damaging to them!