Cold sore: Viruses or localised infections can cause the eye to redden â the problem usually starts in one eye, but can spread to both. The cold sore virus, which 90 per cent of us carry, can sometimes also infect the eye, causing inflammation.
Endorphins are chemicals, called peptides, that are made in the body. They have much of the same effect on a person as opium or morphine. As a result, they actually lower the feeling of pain in the body and can create a feeling of bliss or euphoria.
What's happening inside the body is the heroin is turning into morphine. Morphine has a chemical structure similar to endorphins -- the chemicals your brain makes when you feel stressed out or are in pain. Endorphins inhibit your neurons from firing, so they halt pain and create a good feeling.