I used tretinoin cream 0, 05% for 2 mnths & my skin became better, but when i stopped, acne came back in 3 weeks. does it mean i should use it always?

Dynamic problem: Acne is not a problem like appendicitis, you get that fixed and you stop treating it. Acne is a dynamic issue of growth and or hormonal changes. It occurs over a broad period of 3-7 years in most but some fight it for decades. You try to find a program that keeps things under control and stick with it until you don't need it.

See a specialist: You need to discuss your concerns with a board certified plastic surgeon or dermatologist. Not all tretinoin creams are the same and you may get a more effective cream or medication at the doctor's office than you can get at target.

Should use longer: Topical acne creams/ gels should be used daily if you do not want acne to come back or get worse. It will take about 6 weeks just to see effect and you have to continue if you want it work. If there side effects then you need to talk to your doctor so medicine can be changed.