being a law student , depending if you are served papers then it may not be a restraining order. Now if you are before a judge then its a restraining order. It maybe be for a short time or a for several year if you need anymore info let me know at - firstname.lastname@example.org !
If you're referring to insurance/medical letter of protection it's a contract letter sent by an attorney for an injured client to a medical service provider (doctor/hospital) agreeing to pay for the medical expenses owed from any future recovery so the medical service provider will wait to charge the injured until the case is over. If the injured client does not recover anything, the injured client would still be responsible for the bill.