Daycare noticed this spot on DD (5.5 months) today. She has a tiny cough but is not otherwise sick. She ate rice cereal for the first time Saturday, had some last night, but also snuck a lick of a mango I was eating on Sunday. Could it be an allergy? Most likely not HFM. She had that a few weeks ago and no one at daycare has had it twice. The spot is right above her bum on the side.