If a patient is discovered to have either bacterial or viral pharyngitis is there a need for them to follow up with the doctor after taking meds?

Yes, especially.....: There are a number of bacteria that have developed a resistance to various antibiotics. It is essential for you to know that your conditions have been treated and that the cause of disease is under control. Sometimes you just kill the easy to eradicate bacteria and when the problem reappears it has more of the resiistant bacteria and antibiotics may not work well.