Hello all, I have had bloody phlegm lately after coughing. At first not much but now it's a crimson color. I have stage 4 lung cancer. It was never showing on any scans but I've read it could be an infection. May last CT scan did show something new but 2 of 3 drs. said they were leaning toward an infection. Would the bloody phlepm start later in the infection? I'm taking antibiotic. Thanks!