File a "Motion to Vacate Default Judgment." Your hospitalization constitutes "excusable neglect." You also have to act diligently to remove the default and you have to show the court you have a meritorious defense. This latter requirement has a low threshold. In other words, any legally plausible defense will be deemed meritorious. A defense that might not be meritorius is one where you owe the other party money and your signature is on a document agreeing to pay. In that case, you cannot in good faith claim you have a meritorious defense unless you signed the document under fraud or duress.
You must file a motion to vacate/set aside the judgment immediately. If you wait too long, the court can deny setting the judgment aside. The court will look to see that you acted quickly to set it aside. Have a record of your visit to the hospital to include in the motion to show where you were on your court date. There are specific legal hurdles to cross with this motion, so I would recommend you seek counsel to assist you.