Was diagnsd with strep throat and comp. a z pack (penicillin allergy). i have since dvlpd very painful sores on the roof of my mouth only. normal?

Not usually: Although a drug reaction called Stevens Johnson Syndrome usually affects the mucous membrane, I suspect that your current problem is just a progression of the initial viral infection causing the sore throat (assuming that strep was not documented). If the problem persists, see your doctor or a dentist. In the meanwhile , ask your doctor if you should continue with ZPak.