I was wondering if anyone here will be willing to post some scientific data to show us why some pimples become HUGE and highly inflamed (red) while others dont?
For example, i had 4 small pimples form on my shoulder blade. 3 days later, 2 are HUMONGOUS, red and feel uncomfortable. The other two... not so much.
I do sleep on my side sometimes, so i thought that exterior irritation causes this, but then again, why are only 2 of these 4 pimples more inflamed? Is it an immune system reaction?
Immunological reaction For unknown reasons, the cells lining the sebaceous ducts also produce inflammatory mediators (IL-1a, IL-b and tumour necrosis factor) so pimples may occur in the absence of bacteria. (Though we have seen in other studies that the immunological reaction is often caused by hormonal sensitivities)
Foreign body reaction White blood cells (macrophages and giant cells) removing the debris may cause a more severe granulomatous inflammatory reaction.
Irritation by lipids Free fatty acids and sebum penetrate the dermis after the duct has ruptured.
There's not really a good answer to your question, too many variables that add up to the final huge pimple. It's sort of like asking, why do some days I have good hair days and some days I have bad hair days? Waaaaaay too many factors to consider there.