The liver regenerates when given the chance- and you have obviously done so.
How do you feel?
Alcohol consumption alone should not be damaging (if moderate), but when all other toxins have to be processed, then the liver gets easily overloaded. Some things are also cumulative (meaning that they are not so easy to eliminate and, if consumed regularly, will just continue to pile up). Essentially, it is not the extreme of abstinence that is important, it is the moderation in everything and practicing regular liver detox days (every other month or so) that counts.