Two years ago i recognized that my lower leg is becoming more like a bow. i want to ask if there is any exercises to treat or what should i do with it ?

Leg issues: This really should be assessed in person. The cause of bowing needs to be assessed. Can't tell you how to proceed without an evaluation.

Tibia vara: Varus angulation and medial rotation of lower legs (bowing) in adolescent age group is often associated with obesity. Consult our primary care provider, who is likely to refer you to an orthopedician depending on the degree of bowing.