Eli5: what is happening internally when a pimple forms and then it slowly turns into a zit with a white top that can ooze the white stuff (pus?) ?

Question

Pretty much what the title says:
The zit starts off as a normal pimple, often times painful before it even begins to show and then after a few days has that dry, white appearance. Where is the pus all these days before and what causes it to turn into the zit?

In: Biology

Answer 1

It basically boils down to a small-scale bacterial infection. To get rid of it, the body causes a local inflammation, guiding more blood to the infected area and making it swell. In said blood are white blood cells, which start killing off whatever bacteria they can find. Dead bacteria and white blood cells finally form the “pus”, which gets its usually yellow-whitish color from them. As the clogged-up pore forming the original pimple still is there, said pus can not flow out and forms the classical white-head.