Skin. Even light methamphetamine use can cause widespread acne due to the drug's effects of dry skin and extreme itchiness. Coupled with the common sensory hallucination factor of 'bugs crawling beneath the skin,' this often promotes obsessive scratching, picking, and resulting in many small sores and facial scarring.kin. Even light methamphetamine use can cause widespread acne due to the drug's effects of dry skin and extreme itchiness. Coupled with the common sensory hallucination factor of 'bugs crawling beneath the skin,' this often promotes obsessive scratching, picking, and resulting in many small sores and facial scarring.