Can herpes (1) cause blisters in your throat and cause your left tonsil to swell very painfully? I had an illness a few months ago that started with awful canker sores, then progressed to painful swallowing with apparent sores in my throat. My left tonsil swelled terribly, and both tonsils were red and had white patches on them. My neck glands were swollen, and I was tired. It was not strep, and I did not have a fever. Could Herpes (1) be the cause?