The closest that I could get to look like that style is to create a character style with underline applied. The width of the underline stroke should be as tall as the type, offset to the right place behind the type. Stroke style: Japanese dots. And the stroke color AND the gap color should be the same color.
Obviously, it’s not exactly like what you submitted. Because A: The underline ‘hugs’ the type to tight, and doesn’t leave some space around. B: The corners are very round, much rounder than the one you submitted.