Following apicoectomy last week, i developed a massive infection. dentist has me on antibiotics, but pain is severe. is there anything else i can do?

Second opinion: Sounds like the apico didn't help. Get second opinion from endoontist.

Pain meds?: Did they give you anything for the pain? You may need to go back for a stronger pain med. If infection not resolving, need to back and have it evaluated again and may require switching antibiotics

2 things: Antibiotics. Call your treating Dentist again. And if your treating Dentist is not a Root Canal Specialist, an Endodontist, ask for a referral.