Can I still sue the Dr. Or is a nine year wait to late.Read Details Please.?

My son was born on 5/5/2002 He had yellow jaundice.His Dr. informed the nurse to put an I.V. in the vein by his ankle,to keep him hydrated,as well as treat him for the Jaundice.they missed the vein when they put the I.V. in and the liquid started flowing into his foot.He was in alot of pain because of it and I was the one that noticed they put the I.V. in wrong.The Jaundice wasn't getting any better,so they had him shipped to another Hospital.His Jaundice was going away on the way to the hospital,in the ambulance.When he arrived there,the Dr told me he didn't need an I.V.I had to take him back to his original Dr. for treatment and he gave me a prescription for Tea Tree Oil,which he informed me to pick up at a Mexican store,that sells all organic products.I thought it was odd,but followed the Dr's orders.the oil made it worse.He ended up with a scar,from a result of it.I made a statement,to the hospital about it and didn't think much of it until recently,my son has been complaining of pain where the scar is and has been limping.He never had a problem before with it,until now.I didn't consider suing as it was just a scar,but now that it is causing him pain,do I have a case and who do I contact?