Measuring a bicycle chain's pitch can be used to identify chain wear and flag the need for a replacement chain and/or cogs and chainrings. Bicycle Chains: Length, Width, What's Best to Buy etc.
An industrial, or scaffold, piercing is made up of two holes that are connected by a single piece of jewelry (usually a long barbell). An industrial piercing is commonly made through the cartilage on the upper ear, with one hole close to the head and the other further down on the outer rim. Two or more industrials on one ear is sometimes referred to as an ear cage.
Swelling is a natural process. Fresh piercings are more likely to swell than a healed piercing. Swelling can occur in the 1st 24hours after a fresh piercing and can last up to 3-5 days. If your piercing is starting to swell or is already swollen, taking a anti inflammatory like Nurofen is suggested.