Does the metallic taste in my mouth after coughing mean I have blood in my phlegm?

Metallic mouth taste. There are many causes for a metal taste in the mouth. Most are systemic and need a internal medical consult to find the answer. They will check diet meds topicals, etc that may be involved. The mouth often reflects conditions elsewhere in the body. Pay attention when our body sends up this kind of signal. It is important.
Need evaluation. There are many. Causes for a metallic taste in the mouth. Tis can be caused by infection, vitamin or mineral deficiency, acid reflux, hormonal changes, metabolic disease such as diabetes and others. The only way to answer your question is with an evaluation by a doctor. Cal your doctor and schedule an appointment.