Sharp tooth pains (for sister)?

"For about a week now, I've been having tooth pains. It's on my right cheek area. But only now have I been in tears over it and, even though I'm going to the dentist tomorrow, I'd still like an opinion on what it could be. It's more like a sharp pain which is so painful, I can't even put my teeth together. If you know what it could be, could you *please* give me some advice."

P.S - This is for my sister.

P.P.S - I'll be honest, my sister has a fear of the dentist. She hasn't been for more than 10 years. Don't get me wrong,[ she brushes and washes (unfortunately not flosses) ] everyday but the dentist is better than a manual toothbrush.

P.P.P.S - The bit in bracket's, don't you think it sounds like a rhyme? :)

Thanks for all the help, John.