Day 3 after tonsillectomy. very swollen & tender lymph glands causing sore neck, teeth, face, and head. is this normal? what can i do to relieve pain?

Yes: If taking antibiotics , after 3 days , might wanna consider changing antibiotic.First 3 days are the worst .You should start to feel progressively better every day thereafter.An antiinfllamatory in combination with the antibiotics usually causes almost complete resolution of these symptoms.

Reevaluation: You may require antibiotics or analgesics. Talk to your Surgeon, the practitioner that is most familiar with your situation.