Phenergan and forearm

my daughter has taken Phenergan in her IV twice now, first time it burned, then subsided, the second time, burned worse and hasn't quit for 72 hours and going. Had a CT and doppler on her forearm to see if there is damage as she has had swelling and the skin is hard to the touch and extremely painful. She has gone to the oral form, trying to still get its anti nausea benefits as little else has helped. She is concerned over what effects the oral might have if it is that harsh of a drug.