What could cause rash, blistering/swelling, and scabbing on ear.. with no history of burns, scrapes, insect bites, or contact with allergens?

? Impetigo: What you describe sounds suspicious for impetigo, a strep infection of your skin. You can have a tiny break in your skin that you were not even aware of, and the normal skin bacteria could then enter in and cause a local strep infection. The "scabbing" is what makes me especially suspicious. Try washing with antibacterial wash, put on antibiotic ointment, and if not better in a few days, see doc.