You might want to discuss all the facts with your doctor and see if it
applies. The time period is after three months in cessation of exposure to
have a repeat skin test.

"Prompt skin testing of all infants and children exposed to a case of active
tuberculosis must be given the highest priority. If the initial tuberculosis
skin test of an infant or child exposed to a case of active tuberculosis is
negative, it should be repeated in three months; early in the course of
infection, the skin test may be negative. During these three months, until
the second skin test is negative, infants and children less than four years
of age and those who have HIV infection or other immunosuppressive
conditions should receive treatment."

http://www.mass.gov/dph/cdc/tb/tbscreenupdate.htm