Hi,
You could be having herpes which is a viral infection caused by herpes simplex virus. It is contagious and requires treatment. Recurrences may also happen everytime the immunity dips. Apart from this there is also a chance of it being molluscum contagiosum if it has developed over a gradual period of time. You can consult through practo along with photos for treatment.
Health Tips
Avoid sharing bottles, glasses or kissing.