Will gastritis from taking iron go away on its own. I have been off the iron for 3 weeks now. Was on iron for 4 months to raise my ferritin levels?

It may. Hoping you do not use any alcohol or Ibuprofen , it may get better by itself, but better to try some rantidine( zantac) or tagamet (cimetidine) once a day for few weeks.If symptoms persist , then you must see a gastroenterologist to make sure there are no other causes of your "gastritis".