Lower lid of one of my eyes is swollen and has been paining for several days,now. Today the swelling has intensified. When I checked inside the lower lid there seems to be a swelling inside and its blood shot red and very painful. The pain has been growing for the last few days with constant nagging irritation. I always wear sunglasses while stepping outside as a habit. This should restrict dust particles from entering the eye. Don't know what it is or why it happened.