what is exactly scar tissue?

[seriouslifter]

Is it underneath the skin? Why do people care if you cant see it? Its not red dots on the outside of the skin right?

[Zandria]

Scar tissue that i know of happens when you inject in the same area often. under the skin a scar forms which makes injecting in the same area difficult and painful. There maybe outer layer scar tissue, not sure of it though. To avoid scaring you should rotate injection sites.