I have multiple abscesses, my face is swollen, and I'm 19 weeks pregnant. What can my dentist do to help?

See below. You need to get those abcesses treated now! You probably need either root canal therapy or extractions. He will probably place you on an antibiotic make sure that the drug he usues will not effect your childs teeth. Antibiotics such as tetracycline can cause discoloratiion in a developing childs dentition.
Seek care now! Your dentist needs to determine what immediate, urgent care is necessary to stabilize your mouth and prevent the infections from spreading. Treatment now can help prevent complications with your pregnancy later.
Help!! They can give antibiotics and tylenol (acetaminophen) based pain med and perform necessary extractions or pulpectomies as needed. It is not healthy for you or the baby to allow your dental health to get that far south. Please see your dentist soon, if they won't treat you see another.