There is some blood stains on my underwear?

You should see a doctor. The blood stains may be related to blood in the urine, with drippage causing the blood staining. It can be serious, but in most cases it is a urinary tract infection, and that is usually handled with some prescriptions medications. Do keep an eye on your penis health; for general penis health,  use a top quality penis health cream (health professionals recommend Man1 Man Oil) . Look for a cream that includes L-arginine, which helps in the creation of nitric oxide, which in turn helps keep penis blood vessels open.