I Have Been Using Clindamycin Phosphate And Nicotinamide Gel And

i have been using clindamycin phosphate and nicotinamide gel and an adapalene gel too in order to treat acne during adolscence.My doctor advised to apply the gel only for 2 months but due to carelessness i have been using it for 2 years and still. It is effective and really reduces acne and i am not having any side effects though i have been applying for 2 years. should i discontinue it? will it produce any problems in the long run when i become an adult such as premature ageing?