About three days ago I started noticing a sore in my mouth and I didn't really think anything of it because I thought maybe I just cut it off a chip or something but then it progressively got worse. My throat has been hurting so bad all weekend and then last night I noticed this pretty large bump underneath my jaw bone a little above my neck.. I don't know what this is and I really need to get it figured out. I'm not the best at going to the doctors even though I'm 15 now, but I really need to figure out what it is because I'm a cheerleader and we have competition in about a month and I don't want to miss anything if I do have mono. Please help!!