I know you're sick hoping I quit, but I never will
And even when y'all break out, I be the Benadryl

from Slaughterhouse – DJ Green Lantern "D.O.A." Freestyle Part 2 Lyrics on Rap Genius

Meaning

Even on the slim chance that “you” manage to “break out” — gain a little bit of success in the rap game — Joell will be there to quash it, much like Benadryl will stop an allergic rash or reaction that “breaks out” on your body:

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