At first glance, a sunburn may not seem like a big deal. Your skin is a little pink, maybe a little tender, and you assume a day or two of aloe vera and moisturizer will take care of it. But later that evening, something feels different. The redness has become increasingly painful. A headache begins to set in. You feel exhausted, slightly nauseated, and can’t seem to drink enough water. Suddenly, you’re wondering ...