Hello! My Name Is John, I'm 16 Years Old, I'm

Hello! my name is John, i'm 16 years old, i'm from portugal, school is about to start and i have a huge ''bubble'' on my nose , a friend says its a sebaceous cyst but i dont know what to do! I definitly dont want to go to school with it on my nose, what can i do?! :s
Here's the link of a picture of the ''bubble''
https://scontent-mrs1-1.xx.fbcdn.net/hphotos-xtp1/v/t34.0-12/0000_0000_0000_n.jpg?oh=0000d6fcabcca3a1aadee45b8c79&oe=55EF54DD