Well why don't you try an over the counter medicine for it? In the mean time: avoid touching it, keep washing your hands, don't put lip balm on it (when its gone the lip balm may transfer germs back again causing another one) and keep drinking lots of water. It will be gone soon, don't worry.
My computer glitched, so I'm going to try posting again...sorry if its a double post. Sorry Zoider, if what she has really is a "cold sore", then salt wont help. A cold sore is Herpes, and the only things that will help it go away is a cream like Abreva, taking Valtrex, taking an L-Lysine supplement, or just waiting it out. Salt will, however, help canker sores and ulcers. If you get actualy cold sores often, as a preventative you could try taking 500 mg of L-lysine daily...you can find it in the vitamin isle, or you could talk to your doctor about taking valtrex daily. Also, eating foods high in Arginine during a herpes outbreak or cold sore will aggravate it, so stay away from nuts and chocolates!