I very often have spots. I use such recipe: I grate onions then I put this mix in the form of a mask on the face. The inflammation dries up and in more likely heat-spots disappear.
I would not began to do such masks of onions on all face. In general that so it is possible to burn a skin especially if it very sensitive. Yes probably containing substances in onions also give it antibacterial properties thanks to which there can be an improvement of a condition of a skin. But all the same it is dangerous, after all such mask can irritate mucous covers of a nose and eyes. It is better to put such mix not on all face but only on a heat-spot.
I read that the reason of occurrence of spots are organism malfunctions. And to get rid of spots for ever no masks will help. It is necessary to establish the reason of occurrence of spots only by means of the expert.