Will masturbating cause pimples?

No: It is not usual that masturbating causes pimples(acne). If you are having a problem with acne, you can start out with a good skin cleansing twice daily with a product specifically design for your skin. If this does not work, see a provider for advice.

Masturbation: Nope. Those are probably caused by the hormone fluctuations in your growing and maturing body. But, sexual activity has nothing to do with this skin issue.