Why do iget hives and nomb after shooting heroin?

Experiencing hives and numbness after using heroin could be due to an allergic reaction to the drug or its impurities, as well as potential side effects from its impact on the nervous system. Heroin can cause the release of histamines, leading to skin reactions like hives. Numbness might result from reduced blood flow or nerve compression due to the drug's effects on the body. It's important to seek medical attention if you experience these symptoms, as they can indicate serious health issues.