What is this large bump on my gum?

I'm 15 and i still have a baby tooth. it was becoming a little loose today so i was trying to loosen it some more so i can pull it out. after a few hours this big bump appeared on my gum above the loose tooth. it started to throb really bad and the side of my mouth started hurting.. i am in bad pain. my dad gave me some gel that numbs it temporarily. i can still feel it pulsating but its numb.. what is this bump? my parents are gonna set up a dentist appt. tomorrow so what will happen? will they pull the tooth for me? and will i get any medications if i do for after?