Should i tell the guy i love who has a girlfriend that i love him even though he tells the whole world and ..?

i am really shy from boys bcs i came from an all girls school. Ok there is 3 days left and i will never see him in my life but what if his gf gets angry and..,..what if his friends make fun of him? When i tell about my feelings? Pls im serious and i beg u from all my heart "pls help meeeee"