I am 67 yr old and healthy except for slightly elevated BP for which I take a pill a day.I m 5ft 6 in tall and weigh 160 lbs.I normally take 25 mg viagra periodically for sex.Last time I took viagra but didn t have sex and the erection continued for several hours.Later on I saw several spats of blood on my night trouser though no pain was felt. I got scared of the blood.Can you advise on what could have happened and what to do.Thanks.