Hi, thanks for query, Bleach fumes contains sodium hypochlorite. The first exposure to respiratory tract is causes irritation to throat ,Breathlessness coughing etc. The eyes may also become red and start burning, and there may be pain in the throat. In severe cases, bleeding may occur in the throat and mouth. Inhaling too much bleach can also lead to delirium and confusion. The person may forget where he or she is or what he or she has been doing. Headaches are also common, even in the days following the inhalation exposure. If the person has had skin contact with the bleach, skin irritation and burns may also result. Vomiting and stomach pain are also not uncommon. The person should also immediately drink a glass of milk and move to an area with plenty of fresh air. Taking long, deep breaths and exhaling slowly can help clear the lungs of the sodium hypochlorite gas. As you have mild headache with mild sore throat your exposure is not too much so nothing to worry about brain damage. Thanks.