Blood in one’s sputum is always worrisome especially when it persists for a month or more. It could be coming from your nose or sinuses or from your lungs, this last most commonly caused by smoker’s bronchitis.
Rather than ignore this and/or wait for it to clear spontaneously, I recommend that you see your doctor or better yet an ENT specialist recommended by your doctor. You should also definitely also have a chest X-ray.
Good luck
That's exactly what happend with my mom .. But she's not a smoker never had never will.. She started coughing up blood not a lot but a little. The next day we went to the doctors to find out what caused it. And the doctors said that she had a cut in her throat.. She got better after a few weeks. So don't worry it's normal but if you have a concern you can go to your doctors about it.