I took testostetone once from my doctor, and it seemed my tedticles got smaller. It has been a year and they are still small. My tt is really low agai?

Testicle size. Testosterone would not be expected to make your testicles smaller. It is far more likely that whatever condition you have that created the need for testosterone injections (like a history of mumps, exogenous estrogens, certain toxins, etc.) is what is making your testicles small.