I have been on antibiotics for 5 days to treat cellulitis in my armpit, its not improving and very sore, what should i do?

Axillae armpit: Without pictures, it is difficult to tell what you have. But if the current treatment ordered based upon a clinical examination is not working, return to a clinician for a reevaluation as soon as possible.

See doc: Sounds like you may need to either have a different antibiotic, or, more likely, need surgical drainage of an underlying abscess. Should see your doc.