My skin is already looking better after using this for only a short time. It says to use twice a week and that is probably sufficient. I didn't notice any burning sensation, just a slight tightening as it dried. I have sensitive skin so would notice any uncomfortable side affects if there had been any. I don't plan on wearing it out in the sun, don't know why anyone would. It is only supposed to stay on 10 minutes so surely anyone can stay inside that long. I'm not even sure why some are bringing this up. I like the product and the results it causes. My skin feels better and my skin tone seems a lot better. I've always had a little trouble with oily skin but not with acne and this seems to even it out.