Dermatologist prescribed me tretinoin 0.025% and benzoyl perox/clindamycin gel for my acne. It's not really effective for me. Anything else I can try?

Yes. There are many different formulations and treatment regimens for treating acne. If the one your doctor has prescribed has not been effective, schedule a follow up appointment to discuss alternatives.
Revisit ur dermatologist. tell him / her that the treatment wasn't effective, given that you followed all the instructions well, what your dermatologist gave you sounds standard and many patients improve with, but some patients need different approach if the initial treatment doesn't work, unfortunately there is no magic bullet, acne treatment takes time, effort and regular follow up with your doctor.