He is only giving you inh? Therapy for active tb should contain at least 3 or 4 different drugs. If you have tb, inh alone will not help much. Check with another specialist.

Tb skin tests don't make much sense for ppl who had bcg vaccination, cos their tests mostly come out positive. Go ask for a quantiferon test.

There should be some fast smear tests which can be applied on your lung tissue in order to determine whether it is tb or not. Sometimes tb tissues show pathological signs like certain enlarged cells. Although it takes weeks to grow germ cells out of the given tissue, this is the only way to determine the specific bacteria and whether they are drug resistant or not.

Does your current doctor have any experience with tb? Just make sure he is not panicking and reading tb scars into your x-ray cos your skin test was positive. Do you have other symptoms like fatigue, night sweat, weight loss or constant cough?

Not much blames on your doctor, cos tb is contagious and you certainly don't want to infect your family and friends. Once infected, the bacteria can stay dormant for decades before causing active tb. Since, nowadays, tb is not wide spread in industrialized countries, many doctors fail to read the signs or don't prescribe the right cure. Make sure you get the appropriate diagnosis and treatment. Good luck!