From doctorslounge.com I found this explanation. You can find lots of information with a quick google.
Hi there -- In theory your TB infection remains latent and so there is a (very minimal) risk of recurrence. In practice it almost never happens, but there is a remote possibility of transmission, so it is regarded differently than in a patient with no history of TB at all. Having taken the medical "cure" makes you, for all practical purposes, "cured." Then again, anyone can become infected or reinfected via exposure to active TB, so it's never totally out of the question. You're highly unlikely to ever have the problem again, but you should test positive every time (although even this isn't a 100% ironclad rule either).
As for the scar, most of them remain indefinitely, which is what defines scarring. However, and once again, this is not a sure thing, and it could at least become minimized and may eventually be difficult to detect. However, don't be surprised if it does show up on each X-ray, which means this is something that needs to be noted in your medical records so as to avoid raising a flap every time someone notes it.
