I Am 34 Years Old And Have Had Acne Since

I am 34 years old and have had acne since I was 10. I have been using Retin-A for over a year and have seen zero improvement. For about 6 weeks now I have been using Clindamycin BID and Retin-A at bedtime. I have now developed blister-like acne on my chin. Could this be a side effect? Should I continue using the medications? I have no improvement of my acne at all.