Thanks for coming to HCM
considering your mothers case diagnosed of having MDR and has taken proper second line treatment for 2 years...again there is eruption...
You must go for FNAC of the new eruption and see whether it is TB or not. If it is TB again go for culture and sensitivity for full first and second line drugs.
Many a times it happens that the TB gets cured but the new eruptios are there because of body reaction to mycobacterial protein.
In the meantime you must monitor for her weight and other cardinal symptoms of tb
If it TB and is MDR only again you may have to take treatment but if it is XDR i.e MDR plus resistance to any injectables like amikacin
or capreomycin and to any of FQ like levofloxacin
then you have to take category % regimen....