The opening on June 19 of Clayton Patterson’s show, “Outside IN,” at the Howl Happening gallery, at 6 E. First St., was quite the happening. “It was a great L.E.S. gathering,” Patterson said. The exhibit, which runs through Aug. 14, features the full range of Patterson’s artwork from over the years, from cabinets festooned with found objects from the Lower East Side’s streets — from teeth to bullet cartridges — to a custom-painted electric guitar and the celeb-coveted Clayton Caps. Also in the show are some beautiful paintings by his wife, Elsa Rensaa.