We have all pretty much known the following:
Seek medical attention right away if any of these SEVERE side effects occur when using Viagra:
Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); chest pain; fainting; fast or irregular heartbeat; memory loss; numbness of an arm or leg; one-sided weakness; painful or prolonged erection; ringing in the ears; seizure; severe or persistent dizziness; severe or persistent vision changes; sudden decrease or loss of hearing; sudden decrease or loss of vision in one or both eyes.
So it doesn't suprise me that these side affects can be long lasting.