Finding an ingrown hair a few days after shaving, waxing or epilating is frustrating. It’s caused by hair curling into and getting trapped underneath the skin, and it can be itchy and painful.

A curling iron is one of the best ways to turn up the volume on your hair. But the market is awash in options: Titanium or ceramic? A ½-inch or 2-inch barrel diameter? Which is best for tight curls or ...