several zits grouped together on someone's face or back (or anywhere zits are prolific)

A phrase to describe someone who is cognitively degenerating. Synonym of "going off the deep end". Can have varying degrees of severity.

Reference to the song "Hey You" by Pink Floyd. The line "and the worms ate into his brain" makes no sense in an otherwise linear and literal narration throughout the lyrics.

Its cross between a zit and a pimple. That stands out like you have a red skittle on your face.