sure it'll give you an unnatural hard-on, but also:

VIAGRA is prescribed to treat erectile dysfunction (ED).

We know that no medicine is for everyone. If you use nitrate drugs, often used for chest pain (known as angina), don’t take VIAGRA. Taking these drugs at the same time could cause your blood pressure to drop to an unsafe level.
Talk with your doctor first. Make sure you are healthy enough to have sex. If you have chest pain, nausea, or other discomforts during sex, seek medical help right away.

The most common side effects of VIAGRA are headache, facial flushing, and upset stomach. Less common are bluish or blurred vision, or being sensitive to light. These may occur for a short time.

In rare instances, men taking PDE5 inhibitors (oral erectile dysfunction medicines, including VIAGRA) reported a sudden decrease or loss of vision in one or both eyes. It is not possible to determine whether these events are related directly to these medicines or to other factors. If you experience sudden decrease or loss of vision, stop taking PDE5 inhibitors, including VIAGRA, and call a doctor right away.

Although erections lasting for more than four hours may occur rarely with all ED treatments in this drug class, it is important to seek immediate medical attention. Erections lasting more than six hours can result in long-term loss of potency.

I've experence a blue tint in my vision.

Unnatural hard-on. It's true!