Tooth Abscess

Hi, I had a toothache in my back molar for about a week and a half. A constant throbing sharp shooting terrible toothache from a really decayed back tooth. About a week ago I started taking Erythromycin and have been taking it as told. Now today my gums and cheek is swollen. The Dentist switched my antibiotic to Clindamycin and I just started taking that because he doesn't think the other one was working....no kidding. My question is do you think this antibiotic will kill the infection and when will the swelling go down. The appointment to have my tooth removed isn't until the 10th of april.  I've never had an infection in my mouth before so it's got me really worried. My tooth did stop hurting mostly though since my cheek swelled up, not sure why, is that good?
Thanks, and any advice will be appreciated.
Kally

[kally1]

I also wanted to add that I don't see any pus sack on my gums or cheek but there is some white stuff that looks like it could be an abscess inbetween my tooth and gums. The dentist hasn't seen me since my cheek swelled up and won't beable to until the 10th. thanks, again.

[scottma]

Removal of offending tooth ASAP is advised