It is very possible this pus is simply a drawing out of toxins caused by the pulling. I have been reading a lot of posts on this forum and there have been several people who have noted what looked to be little blisters of pus or sores after pulling for awhile (that later healed). One person had a small sort of whitehead blister that appeared after pulling a number of times. It is possible this is simply part of the healing process and actually a good sign...? If there was not pus before maybe the oil pulling it drawing it out. If the tooth/gums are very infected it may take time before the pulling will be able to draw all of it out. I would wait to do anything drastic and see what the next cleaning reveals. Don't despair!
The oil of oregano idea mentioned also seems like a good thing to try.