The device is called a Painless Laser Epidermal System or P.L.E.S. or "Please" as it is pronounced. It essentially makes tiny holes in your skin through which medication is absorbed. Supposedly no subsequent bleeding would occur. I guess the holes heal instantly. It's also completely silent, so that "whoosing" sound of the hypospray in Star Trek was a total tease.
Granted, there are some Star Trek technologies that are a long time away, such as light-speed travel. And there are those that simply won't exist like transporters (unless you want to be dead on arrival). It's getting to the point where Gene Roddenberry's estate should take a cut of every invention inspired by Star Trek. I'm kidding. Mostly.