Liver

I have been consisntently taking 3-4 Lortabs 10/500 all at once in the evening for quite some time now.  I have been doing this off and on for about three years.  Some times I go about 6 months with no pills but there are other times that I take them everyday for 2 months straight.
I have currently been taking them every night (at once) for the past few months and I am becoming VERY concerned about the shape my liver is in.  I have been having sharp pains off and on underneath my right rib (liver) and also have aches across my whole lower back.  I know that this has to be caused from the excessive amount of tylenol that I have ingested. I have never had my liver tested in the past.  As of two weeks ago, I began taking 2 capsules of milk thistle per day to try and help my liver out during these hard times.
My questions are:
Does milk thistle help?
Does drinking a lot of water help?
Is there anything else that I can take to help my liver?
What kind of long term damage have I caused so far to my liver?

[Burton Dunaway, PharmD]

Taking more than 4000 mg of Tylenol per day can damage the liver. Milk thistle will not prevent liver damage.  You are taking less than the maximum daily dosage , but it is still possible for liver damage to occur. Lortab should be taken every 4 to 6 hours not 4 at a time. If one Lortab is not effective you should consult your physician for a stronger pain reliever that does not contain as much Tylenol.