Welcome to JA and im sorry to hear about your inhalation of rust.
Now the first thing is that you have been vomiting black/brown colored fluid, this is a very concerning point as this can indicate bleeding from the gastrointestional tract. Whenever bleeding is present inside the stomach and it stays there for a period of time, then it can change it's color to black or even dark brown. This is a very SERIOUS symptom and requires you to see the doctor urgently, secondly if you are passing black colored stools as well along with this, that can be another indicator of ongoing bleeding from the stomach. If there are symptoms like dizziness, lightheadedness as well as sweating, this could mean the bleeding is affecting your blood pressure and you will have to go to the ER as soon as possible.
Now while the discoloration can be due to swallowed rust particles but i wouldn't take a chance and attribute these symptoms to simply swallowing of rust until a complete medical evaluation is made.
Now inhalation of rust particles or iron oxide can lead to the development of a lung disease known as siderosis however it is usually a benign disease doesn't cause that many symptoms. But in your case since you have been spitting up blood and i believe that you might be coughing up blood as well, then this is straight indication that you need to be evaluated in a hospital setting. Its possible that the bleeding is due to damage to the lungs caused by the rust particles. Although the rust doesn't usually cause extensive damage to the lungs but its possible that it was mixed with some other chemical or irritant which is now causing the bleeding.
Its likely that you wont have any long term effects from this but its essential that a complete medical evaluation be done as soon as possible to rule out any long term effects or even any acute effects such as gastrointestinal tract bleeding or even bleeding from the lungs. My suggestion is that you should contact your doctor so that he can examine and if needed get a chest xray done to start with. If after an examination he does determine that you are bleeding from the stomach, then an endoscopy might be needed as well.
I would strongly suggest that you contact your doctor immediately or even go to a nearby hospital for evaluation.
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