Severe tooth pain after initial root c treatment?

I went to the dentist 4 days ago to get a root c in one of my lower molars. The dentist could not finish because I had an infection around that tooth. He put an antibiotic in it that hardened and sealed (and it smelled like iodine). The first day after the visit had no pain but the past 3 days have been bad. Today, it has been worse. I cannot even bite down with my front teeth without having a sharp pain in my molar. I have an appointment on Tuesday but I need something done. What should I do and what could be causing this?