Your blood won't boil above 62,000ft / above the Armstrong Line or in space. For a normal blood pressure of approx 120/80 (gauge), 80 Torr = 10.7 kPa. At 10.7 kPa water will boil at 42.3 deg C, which is above body temperature.
Though the above is generally true, there will probably be localised regions where the pressure falls low enough small pockets of vapour to form, causing the vapour pressure to rise. Water in soft tissue will boil which would be pretty painful, but you wouldn't explode.
The problem would be getting to this point without blowing out your lungs or intestinal tract, and staying conscious. Don't try at home.
Human Body in a Vacuum