balms, hand or facial cream, sun
block etc. If a virus, you will have to avoid using the same wash cloths or towels. Apply something that will moisturize the lips, such as a chap-stick with each person using his/her own. Do NO, rubbing, scratching, or picking of the lips, as even mild trauma will spread the virus or enhance the allergic reaction, whichever it is. With good hygiene and avoidance of all potential allergens, this problem should self-cure in a few days to a week.