The puss formed in your tonsils indicates waste matter from your lower intestines is backing up and dumping some of it in the throat area. Their (tonsils') congestions holds back dead cell material and bacteria (=puss). The tonsils, which are the key blood cleansing organs for the head area try to excrete these things, hence the white spots. You learn to move your tongue into the tonsils and remove the puss that has come to the surface.
The past infections merely show that the same problem was there when you were younger.