What Causes Small Blotches On Chest And Back Along With Lower Back Pain?

My husband has been ill for several days with severe lower back pain, nausea, fatigue, blotchy red face (particularly around the eye area) and a few small blotches on his chest and back, headache and tender eyes. This is his second day on antibiotics (amoxicillin) and Panadol 500mg and he is only feeling marginally better. He has no history of high blood pressure.