I presented with significant headache last Friday and jaw pain on the right side (there was a canker sore) and came down with 102.5 fever. My whole face hurt by the next morning, my throat hurt, my lymph nodes were swollen, body aches etc. I went to Acute Care on Saturday and they gave me penicillin for strep. My mouth was much worse by Monday after 8 doses but the fevers were controlled. I contacted the Acute Care. They said the strep test was actually negative but to keep taking the penicillin. It is now excruciating to brush my teeth. My gums are severely inflamed and I have canker sores popping up. Do you think this is part of the initial problem or could I be having an allergic reaction to the penicillin?