I recommend that you go back to see your the doctor
who prescribed this antibiotic to you for another checkup on the progress of how your pneumonia
is resolving. It is good news that your doctor thought your chest was clearing, and if you are otherwise feeling better (no fever
, no shortness of breath, less cough) then it is very likely that you are moving in the right direction.
However, red spots in your phlegm are most consistent with small amounts of blood. It is actually pretty common to have a small amount of blood in your phlegm as you recover from a pneumonia. This is because the chronic coughing causing irritation to the lining of the tubes on your lungs, causing small amounts of bleeding. However, there are a few other things that could also cause bleeding, including a worsening or new infection. Your doctor can evaluate you closely and make sure that there is nothing serious going on.
In the meantime, if you start to experience large amounts of red material in your phlegm, such as large clots, then you should go to the emergency room for more immediate evaluation, as significant bleeding from the lungs is a very serious problem.