Could nitric oxide make my small blood vessels in my penis open back up..?

Possibly: The so called "nitric acid pumps " available are suspect in my opinion about doing what you wish. I suggest , if you want to take something, get L arginine, known precursor to nitric oxide. 500 mg 2 times daily . Known as the poor mans Viagra (sildenafil) and some docs are using this to treat hypertension. your doc may consider nitroglycerin tabs under the tongue.....used for angina . Carefully