Hi, I Was On Azithromycin (500mg Once Daily) For The

Hi,
I was on azithromycin (500mg once daily) for the last 3 days because of a throat infection. The throat feels ok But in the last 2 days I have developed pericoronitis. I guess this means azithromycin is not working is not working or my pericoronitis bacteria has become resistant to it. What should I do?
What other antibiotic can I take?
Please help.