Ive got a sunburn like feeling on part of my scalp. It has persisted for 4 days now, but i dont recall even really being outside. My wife looked at my head and said the spot that hurt was red, but that was it. I tried looking and didnt see anything, no bruising, burn, nothing. I am taking terbinafine for a fungal nail infection. Is this a side effect of that, or any reason to be alarmed?