My wife has a very red left eye, looks like a burst vessel. We took a close up photo and there appears to be a raised blood blister style thingin it.?

Bloody eye. What you are describing is most likely a subconjunctival hemorrhage, which is a benign rupture of a blood vessel in the eye (usually from sneezing, coughing, straining). However, due to the blister, this may best be evaluated by your doctor.
Depends. It could be a burst vessel but it would need to be seen to know for sure what is wrong. If she is experiencing loss of vision but no pain this could be an emergency. There could also be something in the eye causing inflammation or infection so it is definitely worth having it further evaluated.
Subconjunctiva bleed. You describe a common problem called a subconjunctival bleed, which is just as you describe - a burst vessel. If so, they generally do not cause any other symptoms, specifically no pain or change in vision. They can happen with sudden stress like sneeze or cough, and sometimes they just happen. If her eye hurts, the redness is only around the iris or vision is affected, be seen.