I am licensed in Nevada, but this answer should apply in California as well.
I am assuming the treatment was given in California. The Statute of Limitations for medical malpractice in California is 3 years from the date of the injury, or one year from the date the plaintiff discovers or reasonably should have discovered the injury, whichever occurs first. If the medical malpractice action is based upon the presence of a foreign object found inside the plaintiff's body, the statute of limitations does not start to run until the plaintiff discovers, or should have discovered, the object. The periods of limitation for medical malpractice apply to minors six years of age and older.
So, it is fact specific in a case such as yours - when did you discover, or when should you have discovered the gauze in your body? Add one year to that, and you have the date on which the suit must be filed.
I recommend that you speak to an experienced personal injury lawyer in your area to discuss the case.
Probably not. You only have one year from the "date of the discovery" of the foreign object being left in you. How did you find out about this and when? Without knowing this, I can't answer your question.
You need to meet with an experienced med-mal attorney. You have two issues. The first is Statute of Limitations, which will depend on when you “knew or should have known” of the facts that support your cause of action. In other words, it will run from when you learned about the retained foreign object. You can extend this period a bit by sending an intent to sue notice. See an attorney ASAP.
Your other issue is damage. Were you injured by the gauze left behind? Infection, scar tissue or adhesions would be an injury. Again, an attorney can help.
Best of luck to you.
This response is intended to be a general statement of law, should not be relied upon as legal advice, does not create an attorney/client relationship and does not create a right to continuing email exchanges.