Drinking leads to a build-up of fat in the liver. If drinking stops this process reverses in around 2 weeks.
Drinking alcohol over a long period causes inflammation in the liver sites. Binge drinking is associated with the same effect. Mild alcoholic hepatitis is usually reversible with permanent abstinence.
This is where the liver is made up of scar tissue rather than healthy liver tissue. This is irreversible. Stopping drinking can prevent further damage. Continued drinking has a very poor prognosis.