Iam using hydroquinone 2% retinion 0.025% mometasone furoate 0.1% for more than 2 years. Now I stopped it became more darker. Please help me?

These are temporary. These agents are not permanent, they just interfere with the production of melanin, the pigment that causes your discoloration. You have to continue to use them for life, at least intermittently, or consult a laser specialist.