What physical sign of cannabis use can be characterized by red, irritated appearance?

The physical sign of cannabis use that can be characterized by a red, irritated appearance is bloodshot eyes. When a person consumes cannabis, the active compound THC (tetrahydrocannabinol) causes the blood vessels in the eyes to expand, leading to a noticeable redness. This phenomenon occurs because THC lowers blood pressure, which in turn causes the eyes to become more vascularized and appear bloodshot.

This reaction is commonly associated with cannabis use and is visually distinctive, making it easier to identify compared to other signs of use. Other options in the question do not directly relate to a red or irritated appearance; for instance, piloerection relates to goosebumps and is not visually apparent in the same way. Dilated pupils can occur with a variety of substances, including those other than cannabis, and while relaxed inhibitions may be a behavioral sign, it does not manifest in a physical characteristic.