I had a tooth pulled two days ago. The dentist prescribed me Tylenol 3 w/ codiene and Ammox. I had been taking my medication normally without problems, but last night my face broke out in hives. They were raised dry itchy places ride on my cheeks and nose. Could it be a reaction from my meds? I woke up and the hives are almost gone. Am I allergic to something I'm taking?

Hives are most definitely a symptom of an allergic reaction to something. And somethng you need to take seriously.

Have you taken ammoxicylin before without any problems? I would definitely call the dentists office today.