Is it a zit or cold sore?
This is gross but depending on the color of puss, if you have pain, and the location, it could be a number of things. Sounds like a cold sore that popped up for any number of reasons like lack of sleep, sharing makeup, touching your mouth, etc. Zits definitely don’t spread. You can injure your skin by touching and popping them but they don’t spread. Put some lidocaine on and it should clear up in about a week.
