What should I do for pink eye if the antibiotics prescribed didn't work?

Pink eye. Call your eye md for a reevaluation. It may be a viral conjunctivitis, which would be not expected to recover with antibiotics. Also to be safe, you need your doctor to rule out other causes of pink eye, such as inflammatory disease.
Return to your doc. If something doesn't respond, it either means needs more time, incorrect diagnosis, wrong dosage, resistant to therapy, or more than one problem. Typically, for a viral pink eye, topical antibiotics are just prescribed for prevention of secondary bacterial infection.