I honestly couldn't say if it would burn. If you apply it directly to the sores it will sting for a bit. I have used it on open cold sores at full strength. It dried those up usually in 24hrs. When you take the Miracle-Mineral-Supplement it is diluted with water or juice so that should not burn, but I can't guarantee it. Good Luck! Give it a try you have nothing to lose!!! Keep in touch!