Nuerobion forte injection was given through iv (rl) and has some side affect . what should we do ? would it resede on its own?

This drug contains six B vitamins. What is the side effect you are talking about? If it's due to the medication, it should resolve by itself. If you have phlebitis due to poor injection technique apply warm compress twice a day. You can take the oral B complex in the future it will be cheaper and safer. Using the leg vein for IV drug is not recommended unless there is no vein anywhere else.