It depends entirely what is causing your liver to be enlarged.
How do you know it is enlarged? Are you seeing a doctor what does your doctor say?
If you are not seeing a doctor I would start there.
But the best thing you can do for your liver while waiting to see your doctor is if you drink to stop immediately.
You asked what is hepatitis.
Basically hepatitis means liver inflammation "hepa" meaning liver and "-itis" meaning inflammation.
If you are asking about hepatitis virus that is a virus that causes liver inflammation like Hepatitis A, hepatitis B, hepatitis C and so on there are a number of viruses in that family of viruses.
First you need to know what is causing your liver to be enlarged. Is it from alcohol? Do you have chronic hepatitis B or hepatitis C?
Do you have NAFLD (Nonalcoholic fatty liver disease)? Have you been taking certain medicines for long periods of time at high dosages?
Have you been diagnosed with liver cirrhosis?
So once the underlying cause is treated you liver if not too badly damaged may with time return to normal size. If your liver has too much damage and is failing or if you develop primary liver cancer (HCC or Hepatocellular carcinoma) you would need a liver transplant to survive.