I have a very large gum abscess on the roof of my mouth, right behind my front teeth. i am on day 3 of a 10 day course of antibiotics (climdamycin 300mg). the abscess is not any better at all. should it be shrinking by now?

Continue treatment and if no better in another 24 hours would see ENT or your dentist for further evaluation and treatment.

Antibiotics may take a few days to mitigate an infection. Once the infection is reduced your dentist can commence with the appropriate care.

it can take 48-72 hours for antibiotic to begin to gain a foot-hold. It is important to continue with the medication for the full 10 days, even if you feel better in less time. If the swelling does not begin to abate in an additional 24 hour, contact your Dentist.