That depends on whether you're skeptical you have Lyme to begin with. Sounds like you're not since you've been treating for a few years. If you still have symptoms then I don't see the point in shelling out a minimum of $595 for the test just to disprove how you are feeling.
As far as the test goes, I've never had it done but it's supposed to be somewhere around 80% accurate. It may miss some because Borrelia like to hide in tissues and tendons and bone so I'm not sure if it would always be detected in the blood. Also, what if your symptoms now were because of another bacterium such as Bartonella. The test would then come out negative yet you still would be dealing with an infectious situation.