What is the difference between a pedophile and acne? Acne waits until you're 12 to come on your face
I don't understand why you would make a joke about sexual assault
It means the acne would be better to come on your face later and then nobody would laugh about it when you are 12
To make a joke about someone enduring sexual abuse as a child is very offensive, especially if you then suggest that having embarrassing acne is even worse.  Some children endure extreme harm at the hands of predators, and this is no laughing matter.