How Long Does Ulcer In Throat Take To Heal?

Hi my hubby is having an ulcer on the right side near the tonsils. it been almost 2 weeks now. It started after having an antibiotic (klacid) for fever. now he had antibiotic for ulcer for 3 days. today was the 3rd day. But the ulcer is still the same. May be bit relief is there. thats it.Does it take time to heal as it is near to tonsil area.