I have normal liver usg but with mild hepatomegaly (i am a daily drinker) - no sign of fat. all blood tests are also normal. if i abstain from alcohol for at least 30 days would it be something significant for liver to shrink back to normal size?

I don't know the time course for your liver to decrease in size but cutting down on your alcohol would be a good idea since you already have hepatomegaly. I'm glad your liver enzymes are okay so far but why tempt fate? Your liverresponsible for synthesizng albumin and degrading &recycling blood products & metabolizing medications- don't mess with it!